A Traffic Modelling Update Report - Abode Group

HE/A14/EX/

44A14Cambridge to Huntingdon

improvement scheme Development Consent Order Application

Traffic Modelling Update Report

TR010018

HE/A14/EX/44 Development Consent Order Application

Traffic Modelling Update Report

June 2015

The Infrastructure Planning (Applications: Prescribed Forms and

Procedure) Regulations 2009

hampsob

Typewritten Text

hampsob

Typewritten Text

hampsob

Typewritten Text

Registered office Bridge House, 1 Walnut Tree Close, Guildford GU1 4LZ

Highways England Company Limited registered in England and Wales number 09346363

A14 Cambridge to Huntingdon improvement scheme

Development Consent Order Application Traffic Modelling Update Report

HE/A14/EX/44

15 June 2015

HE/A14/EX/44 Page 2 of 127 June 2015

Table of Contents 1 Introduction 4

1.1 Purpose of this report 4

1.2 Structure of this report 4

2 Traffic modelling update 6

2.1 Introduction 6

2.2 Model refinements 6

2.3 Model performance 10

2.4 Traffic projections 12

2.5 Scheme impact on major routes 13

2.6 Scheme impact on local roads 16

2.7 Scheme impact on A14 junctions 22

2.8 Scheme impact on Cambridge 23

2.9 Scheme impact on Huntingdon 31

3 Operational assessment 37

3.1 Introduction 37

3.2 Junction Operational assessments 37

3.3 Modifications required to accommodate CHARM3a 44

3.4 Sensitivity testing of proposed development at Northstowe 47

3.5 Link capacity assessments 49

3.6 Merge and diverge assessments 52

3.7 Conclusions 58

4 Environmental assessment 59

4.1 Introduction 59

4.2 Air quality 59

4.3 Air quality results 62

4.4 Noise 65

4.5 Other environmental topics 71

4.6 Summary 71

5 Economic case 72

5.1 Introduction 72

5.2 Monetised benefits 72

6 March 2015 road traffic forecasts 76

6.1 Introduction 76

6.2 CHARM3a+RTF15 traffic projections 76

6.3 Operational assessment 83

6.4 Environmental assessment 84

6.5 Economic case 86

7 Conclusions 87

7.1 Impact of traffic modelling update 87

7.2 Impact of March 2015 road traffic forecasts 88


Appendices Appendix A: CHARM3a Operational Assessment Tables Appendix B: CHARM3a Operational Assessment Tables (modified junctions) Appendix C: CHARM3a Operational Assessment Tables (high development

scenario) Appendix D: Air quality – predicted magnitude of change of pollutant

concentrations


1 Introduction

1.1 Purpose of this report 1.1.1 The purpose of this Traffic Modelling Update Report is as set out in Highways

England’s letter to the Planning Inspectorate of 12 May 2015 (document reference HE/A14/EX/19), as follows:

• to provide detail on the update made to the Cambridge to Huntingdon A14 Road Model (CHARM) between December 2014 and spring 2015, as a result of revised economic parameters published by the Department for Transport in November 2014, refinements to network coding, and to External to External growth factors1, and the subsequent impact on the assessment of the A14 Cambridge to Huntingdon improvement scheme (‘the scheme’); and

• to provide detail on updated road traffic forecasts published by the Department for Transport in March 2015 and the subsequent impact on the assessment of the scheme.

1.1.2 In addition, this report provides a revised economic case2 in accordance with

the above update made to the Cambridge to Huntingdon A14 Road Model between December 2014 and spring 2015.

1.1.3 Also provided is additional sensitivity testing in relation to a high development scenario, which allows for full build out of development at Northstowe to 10,000 homes.

1.2 Structure of this report 1.2.1 Following this introductory section, the remainder of this report is structured

as follows:

• Section 2 describes the update to the Cambridge to Huntingdon A14

Road Model carried out between December 2014 and spring 2015;

• Section 3 presents the effect of the CHARM update on the operational

assessment of the scheme;

• Section 4 presents the effect of the CHARM update on the environmental

assessment of the scheme;

• Section 5 presents the effect of the CHARM update on the economic

case for the scheme;

• Section 6 presents the effect of revised Department for Transport Road

Traffic Forecasts published in March 2015; and

1 External to External trips refer to journeys which start and end outside the modelled region. 2 This provides an update to section 5 of the Case for the Scheme (document reference 7.1).


• Section 7 provides a summary of overall conclusions.


2 Traffic modelling update

2.1 Introduction 2.1.1 In order to assess the impact of the scheme, a suite of transport models have

been used to forecast expected travel demand both with and without the scheme in place. Details of model development can be found in the Transport Assessment (document reference 7.2, section 3.5), submitted as part of the DCO application in December 2014.

2.1.2 The model which underpins the Development Consent Order (DCO) application for the scheme is version 2 of the Cambridge to Huntingdon A14 Road Model, which is also referred to as CHARM2.

2.1.3 In November 2014, after CHARM2 had been completed, the Department for

Transport published revised economic parameters for application on transport modelling and appraisal of transport schemes.

2.1.4 Since the submission of the DCO application for the scheme, these revised

economic parameters have been incorporated into the model. In addition, following a review of CHARM2, further refinement work has been undertaken. The refinements noted in section 2.2 below for the Base Year (2014) model were incorporated into CHARM2 model to form CHARM3 - CHARM3a is the outcome of further refining the Base Year matrices through matrix estimation, with these refinements incorporated into the process.

2.1.5 The above work has culminated in version 3a of the Cambridge to Huntingdon A14 Road Model, which is referred to as CHARM3a.

2.2 Model refinements 2.2.1 The following section lists the refinements that have been made between

version 2 and version 3a of the model. Of these the most significant are those referred to in Highways England’s letter to the Planning Inspectorate of 12 May 2015 (document reference HE/A14/EX/19), that is, the network coding and External to External growth assumptions for forecast years. However, in order that all refinements can be clearly understood, this section also provides a comprehensive list of the other, more minor, adjustments made.

2.2.2 The following refinements have been made to the Base Year model:

• Incorporation of revised economic parameters issued by the DfT in November 2014. Generalised cost parameters were updated between CHARM2 and CHARM3a. Generalised costs in CHARM2 were derived from guidance in the January 2014 release of WebTAG, specifically unit


A1.3 and the TAG data book3. CHARM3a makes use of the November 2014 release of WebTAG and the TAG data book4.

• Refinements to merge coding on A14 were made to address PM peak journey time validation. This was noted as an area where CHARM2 was not fully compliant with WebTAG guidance. Specifically, the following updates were made:

- saturation flows at the A14 / A428 westbound diverge were increased beyond those of the standardised coding manual. Delays in the PM peak at this location did not correspond with observed TomTom journey time data, thus providing a justification for the increase in saturation flow;

- saturation flows at all merge locations along the A14 were reviewed, with some updates made where necessary;

- the use of Q-markers was reconsidered. Q-markers model additional delay for traffic entering a motorway or dual carriageway from a slip road on the basis of the traffic volume on the main line and on the slip road relative to the capacity of the road. It was considered that, in some cases, Q-markers may have double-counted delays at congested locations; and

- greater use was made of weaving markers5 along the A14 corridor, particularly at low-standard merge locations and those junctions within close proximity of each other (less than 2 kilometres separation).

• A new zone was added to the model to address assignment stability as a result of trip routeing issues. The model is assigned iteratively until it reaches a stable and converged solution. Model stability means that there are only small changes in the routes used between successive iterations. The routeing issue was identified through the comparison of different modelled scenarios which showed trips between the south east and Leicestershire using the M25/M1 in the ‘Do-Minimum’ scenario and the A14/A1 in the ‘Do-Something’ scenario. This was caused by congestion in the ‘Do-Minimum’ scenario which caused the buffer6 network to become a more attractive option for trips between the south east and Leicestershire. The issue was resolved by dividing the zone in two.

• Trip distribution was amended to address routeing issues. This was identified through the comparison of different modelled scenarios, which showed trips using the M11 / A14 corridor between Essex and the Midlands in the Base Year rerouted via the M11 / M25 / M1 in the ‘Do-

3 https://www.gov.uk/government/publications/webtag-tag-data-book 4 https://www.gov.uk/government/publications/webtag-tag-data-book-november-2014

5 Weaving markers are used to simulate delays due to weaving, an undesirable situation that arises when traffic wanting to leave the road at the next junction has to fight for road space with traffic that has just entered from the previous junction.

6 The buffer network surrounds the simulation network and is coded in the more conventional sense of only requiring data to describe the roads as opposed to the junctions.


Minimum’ scenarios before rerouting via the M11 / A14 in the ‘Do-Something’ scenarios. This was caused by congestion in the ‘Do-Minimum’ scenario which resulted in buffer network becoming a more attractive route for trips between Essex and the West Midlands than it would otherwise realistically be. These long distance trips were thus split at an intermediate zone near Kettering to ensure consistent routeing.

• New AM and PM peak hour pre-peak matrices were produced. For CHARM2 the pre-peak hour matrices were derived from unadjusted mobile phone observations. A significant amount of work had been undertaken to adjust the peak hour matrices, followed by matrix estimation, yet this had not been undertaken for the pre-peak matrices. For CHARM3a a more traditional approach was adopted, with sector-based factors applied to the peak hour matrices. These factors were derived from analysis of the traffic count data collected for the model update.

2.2.3 In addition to the above, some further minor modifications were made to the

model network: incorporation of updates to saturations flows, speed-flow curves and signal timing and/or staging (for example, modifications to signal staging and timings on the A10 corridor around Milton and at Milton junction (Junction 33)).

2.2.4 Of the changes made in the Base Year model, most have only minor impacts on the out-turn assignment. The two changes that have larger impacts are the alterations to merge coding on the A14, which substantially improves the PM peak journey time validation on the route, and the changes to the pre-peak matrices, which result in higher traffic volumes in the pre-peak hour, particularly for the PM, across the modelled area.

2.2.5 All of the changes made to the Base Year model were propagated through to the forecast year (2020 and 2035) models.

2.2.6 In addition to the changes applied to the Base Year model, the following refinements have been made to the forecast year ‘Do-Minimum’ models:

• Coding of the ‘pinch-point’ scheme at Spittals Interchange7 in the ‘Do-Minimum’ scenario was adjusted to reflect better the aims of the scheme, notably the adjustment of signal timings.

• HGV penalties were applied to the adjusted network in Huntingdon (as a result of the inclusion of Edison Bell Way). For CHARM2 this penalty had been omitted, leaving a ‘hole’ in the Huntingdon cordon that HGVs could potentially route through.

• External to External trip growth assumptions were updated in CHARM3a. In CHARM2, external trip growth was taken from Cambridge Sub Regional Model (CSRM) forecasts. Further investigation of these concluded that these were, in turn, derived from forecasts from the East of

7 Refer to the Transport Assessment (document reference 7.2, section 7.4.25).


England Regional Model (EERM). It was concluded that it would be better instead to make use of more contemporary national data sources. For CHARM3a, External to External trip growth for ‘light’ vehicles is thus derived from forecasts from the National Trip End Model version 6.2 (NTEM 6.2), with the National Transport Model (NTM) Road Traffic Forecasts 2013 (RTF2013) providing the growth factors for HGVs.

• Speeds in the buffer network were altered in CHARM3a. For CHARM2 the buffer network speeds remained as per the Base Year model. This was considered to be unrealistic. For CHARM3a the fixed speeds in the buffer network are reduced over time in-line with forecasts from the NTM, providing a proxy for increasing congestion in these areas of less detailed modelling.

• A new zone was added to the model to improve the representation of the St Neots Eastern Expansion and Loves Farm developments. For CHARM2 these developments were loaded on to an existing zone (1228) which connected onto the network at Great Gransden, however, this resulted in unrepresentative congestion and delays at an existing roundabout. For CHARM3a a new zone (3059) has been introduced to the east of St Neots, which better represents where traffic associated with these developments would join the existing road network.

• Representation of Phase 2 of the Darwin Green development was altered in the ‘Do-Minimum’ scenario to better represent where traffic associated with this development would join the network. For CHARM2 traffic associated with phase 2 of the Darwin Green development is loaded on to Zone 72, which connects to local roads on the southern edge of Histon to the north of the A14. In reality the proposed access to this development is located on the southern side of the A14; therefore Zone 72 has been connected to the local roads to the west of B1049 Histon Road in CHARM3a.

2.2.7 In addition to the changes applied to the Base Year and ‘Do-Minimum’

models, the following changes were made to the ‘Do-Something’ models:

• HGV penalties were applied to the adjusted network in Huntingdon (as a result of the inclusion of new at-grade links from the de-trunked A14 at Views Common Link and Mill Common Link). In CHARM2, these penalties had been mistakenly omitted, leaving a ‘hole’ in the Huntingdon cordon that HGVs could potentially route through.

• A1 coding north of Brampton Hut was updated. An incorrect speed-flow curve8 had been applied to this section of the A1 in CHARM2, underestimating the link capacities that would be afforded by the widening of this section of road.

2.2.8 Of all the changes to the forecast year models, only the change in External to

8 Speed-flow curves are used within the model to reflect the constraints on traffic imposed by the

available network capacity. Speed flow curve relationships estimate the decreases in link speeds which would occur as a result of flow increases, with reference to the characteristics of the road.


External traffic growth factors has a significant effect. The revised application of NTEM v6.2 and NTM RTF13 derived factors has resulted in reduced External to External traffic growth. This has therefore resulted in lower flows on the Strategic Road Network9 in both the ‘Do-Minimum’ and ‘Do-Something’ models and has also resulted in some shorter-distance traffic re-routeing from local roads, ‘backfilling’ onto the strategic routes. This has led to some reductions in traffic volumes on local roads as a result.

2.3 Model performance

2.3.1 The performance of the Cambridge to Huntingdon A14 Road Model has been assessed against the calibration and validation criteria and acceptability guidelines in the Department for Transport’s Transport Appraisal Guidance (WebTAG) Unit M3.1.

2.3.2 WebTAG M3.1 states that ‘all or nearly all screenlines’ should have total modelled flows within 5% of observed flows, where screenlines are lines that bisect two or more roads so that flows across the line can be counted. Screenlines which form a closed loop are referred to as ‘cordons’. Figure 2.1 shows the location of the 8 screenlines created for the purposes of calibrating and validation the Cambridge to Huntingdon A14 Road Model.

Figure 2.1: Screenline locations

9 The Strategic Road Network is the network of motorways and trunk roads in England for which Highways England is responsible.


2.3.3 Table 2.1 summarises the CHARM2 screenline performance for the AM peak, Interpeak and PM peak hours. In the AM and PM peak hours, 94% and 88% of screenlines meet WebTAG flow validation criteria respectively. The Interpeak falls slightly short of this, with 75% of screenlines meeting the criterion for total flows, and 81% for light vehicles. For the majority of cases where either the total vehicle or light vehicle flows do not meet the criteria the flow difference is close to 5%. Across all screenlines, the light vehicle and total vehicle differences do not exceed 10% and are generally in the region of 7% to 8%. In terms of percentages achieving the WebTAG criteria, the screenline performance of heavy vehicles is much lower than that for light vehicle or total vehicles. However, as the flows of heavy vehicles are much lower than those of light vehicles, the differences in terms of number of trips were considered to be satisfactory.

Table 2.1: CHARM2 screenline calibration

Time Period Light Vehicles Heavy Vehicles Total Vehicles

AM Peak 94% 44% 94%

Interpeak 81% 56% 75%

PM Peak 88% 19% 88%

2.3.4 Table 2.2 summarises the performance for the calibration counts at an

individual link level. Cells highlighted green demonstrate more than 85% of links meet the individual link flow criteria (that is, within WebTAG acceptability guidelines); amber highlighted cells are where between 75% and 85% of links meet the criteria (that is, just outside of the acceptability guidelines); and red highlighted cells are those where fewer than 75% of links achieve the criteria.

Table 2.2: CHARM2 individual link calibration


AM Peak 87% 100% 84%


PM Peak 90% 100% 91%

2.3.5 Overall the calibration counts show good performance with almost all vehicle

types meeting either the variable flow or GEH criteria10 for individual links in all time periods. The total vehicle performance in the AM peak hour is the only exception, although at 84% this is only just outside criteria. Of those AM peak links, excluding pre-2014 counts results in an increase in performance to 89% (that is, meeting criteria) perhaps suggesting that lower confidence can be placed in those older counts that have had seasonality and annualisation factors applied; this also holds true for the PM peak, although not to the same extent.

10

WebTAG Unit M3 §3.1.


2.3.6 These calibration statistics have been reproduced for CHARM3a. Table 2.3 summarises the screenline calibration while Table 2.4 summarises the individual link calibration. From this it is apparent that there is an improvement in screenline calibration in two of the three time periods in CHARM3a, with the percentage of screenlines achieving WebTAG requirements increasing from 94% to 100% in the AM peak hour and from 75% to 94% in the Interpeak hour. The PM peak hour screenline calibration is slightly worse, falling from 88% to 81%. The main reason for this is a slight deterioration in the performance of CHARM3a at Screenline 5 in the northbound direction, where the modelled flows are 6% lower than the counts. Hence, this falls marginally outside of WebTAG guidance which is based on flows across a screenline being within 5% of the counts. The screenline performance for heavy vehicles has been improved, particularly in the PM peak.

Table 2.3: CHARM3a screenline calibration


AM Peak 100% 50% 100%


PM Peak 81% 56% 81%

Table 2.4: CHARM3a individual link calibration


AM Peak 92% 100% 91%


PM Peak 94% 100% 94%

2.3.7 Comparing model calibration at individual link level across the whole model,

CHARM3a shows an improvement in performance with all vehicle types meeting either the flow or GEH criteria for individual links in all time periods. Model calibration is improved relative to CHARM2 in all three time periods at this level.

2.4 Traffic projections 2.4.1 Forecasts have been produced for 2020, which is the first full year that the

scheme is expected to open, and for 2035, which is a future year used to assess whether the design of the scheme will be able to accommodate future predicted traffic growth. The forecasts consider scenarios both without the scheme (a ‘Do-Minimum’ scenario) and with the scheme (a ‘Do-Something’ scenario).

2.4.2 These forecasts reflect the best information currently available and are

intended to provide a forecast of the likely travel conditions on the A14 and surrounding road network, both with and without the proposed scheme.


2.5 Scheme impact on major routes 2.5.1 Traffic forecasts with and without the scheme have been prepared based on

both CHARM2 and CHARM3a versions of the traffic model. Forecasts are presented for key sections of the A14 and for a range of other major roads that are likely to experience a change in traffic levels as a result of the scheme.

Without scheme demand

2.5.2 Table 2.5 compares traffic flows on major routes in the years 2014, 2020 and 2035 without the scheme. The rate of growth differs from road to road depending on characteristics such as the amount of congestion and the availability of alternative routes.

2.5.3 The CHARM2 traffic forecasts, which are reported in the Transport Assessment (document reference 7.2), show average growth of the order of 13% between 2014 and 2020 with a further 21% growth between 2020 and 2035. The level of growth forecast in CHARM3a is slightly lower, reflecting the revised assumptions made regarding External to External traffic growth. Between 2014 and 2020, traffic growth on strategic routes is of the order of 11%, with a further 14% growth to 2035.

2.5.4 Despite the differences in the growth assumptions between CHARM2 and

CHARM3a, all sections of road within the vicinity of the A14 are forecast to experience an increase in traffic compared with the existing situation.

Table 2.5: Forecast 2-way AADT

11 flows on major routes without the scheme

Location CHARM2 CHARM3a

2014 2020 2035 2014 2020 2035

A14 West of A1 40,100 44,200 51,500 41,600 45,300 51,600

A14 Spur East of A1(M) 42,600 50,300 63,900 42,100 46,000 53,300

A14 Through Huntingdon 72,900 78,900 90,500 72,700 80,400 90,300

A14 Huntingdon Southern Bypass - - - - - -

A14 Swavesey to Bar Hill 80,200 86,100 93,400 80,300 86,200 94,600

A14 Bar Hill to Girton 91,500 101,000 110,700 91,400 100,300 111,300

A14 Histon to Milton 64,000 75,900 86,600 64,300 76,200 85,800

A14 East of Milton 60,200 69,600 82,300 61,700 70,000 79,300

A1 North of Alconbury 69,400 77,900 97,100 69,600 73,900 81,800

A1 North of Brampton Hut 31,900 39,000 52,100 32,700 36,200 43,500

11

AADT, or Annual Average Daily Traffic represents the average traffic flow in a 24-hour period measured over the whole year.


A1 South of Brampton Hut 34,700 38,700 50,100 35,600 39,300 45,700

A1 Near Buckden 42,200 46,300 53,500 43,400 47,000 52,000

M11 South of Girton 63,700 73,700 83,600 62,800 72,700 83,000

A428 Near Bourne Airfield 33,300 40,800 55,300 33,500 40,900 51,900

A1198 West of Hilton 11,100 13,300 19,400 10,400 11,500 14,200

A141 North of Huntingdon 28,300 25,700 26,500 28,700 29,400 29,500

Units: vehicles per day, rounded to the nearest 100.

With scheme demand

2.5.5 Table 2.6 compares daily traffic flows on major routes in 2020 with and without the scheme. The percentage change in flow as a result of the scheme is reported and has been colour-coded to aid interpretation. Roads where flows are forecast to change by 10% or less are highlighted in blue; roads where flows are forecast to increase by more than 10% are highlighted in red; and roads where flows are forecast to reduce by more than 10% are highlighted in green.

2.5.6 The broad pattern of change is similar in both the CHARM2 and CHARM3a

forecasts, although the scale of change is generally lower in CHARM3a, which reflects the lower External to External growth assumptions.

2.5.7 All locations that are forecast to experience a significant increase in traffic as

a result of the scheme are also locations where the scheme would provide improved infrastructure.

2.5.8 The A14 Spur and the detrunked A14 through Huntingdon would benefit from significantly reduced flows due to long-distance traffic transferring to the A1 and Huntingdon Southern Bypass. Some reduction in flow is also forecast on the A428. Small changes in flow are forecast on the Strategic Road Network beyond the extents of the scheme, with daily traffic flows on the A1 north of Alconbury, the A1 near Buckden, the M11 and the A14 east of Milton forecast to change by 1% in CHARM3a.

2.5.9 The only section of road where the scheme is forecast to have a greater

impact in CHARM3a than CHARM2 is the A1 north of Brampton Hut. Without the scheme flows are forecast to be around 2,900 vehicles per day lower. However, flows are only 1,400 vehicles per day lower with the scheme. This change is the result of some traffic being forecast to use the A1, B1043 and A14 Spur rather than the A14 to avoid congestion at Spittals Interchange (Junction 23) in the Interpeak and PM peak hours in CHARM2. This rerouting of traffic is not evident in CHARM3a, as the reduction in External to External traffic on the A14 has reduced journey times via the A14, making this a more attractive route. Consequently, the A1 north of Brampton Hut shows an increase in traffic, with trips using the Huntingdon Southern Bypass joining the A1 at Brampton junction and using the widened A1 for their onward journey.


Table 2.6: Impact of the scheme on major routes in 2020

Location

CHARM2 CHARM3a

Without scheme

With scheme

% Change

Without scheme

With scheme

% Change

A14 West of A1 44,200 47,600 +8% 45,300 47,300 +4%

A14 Spur East of A1(M) 50,300 22,100 -56% 46,000 21,000 -54%

A14 Through Huntingdon 78,900 14,800 -81% 80,400 11,900 -85%

A14 Huntingdon Southern Bypass - 68,400 - - 65,300 -

A14 Swavesey to Bar Hill 86,100 89,600 +4% 86,200 87,800 +2%

A14 Bar Hill to Girton 101,000 106,000 +5% 100,300 103,500 +3%

A14 Histon to Milton 75,900 84,000 +11% 76,200 81,700 +7%

A14 East of Milton 69,600 71,400 +3% 70,000 70,800 +1%

A1 North of Alconbury 77,900 77,200 -1% 73,900 74,500 +1%

A1 North of Brampton Hut 39,000 61,900 +59% 36,200 60,500 +67%

A1 South of Brampton Hut 38,700 72,400 +87% 39,300 72,600 +85%

A1 Near Buckden 46,300 46,800 +1% 47,000 47,700 +1%

M11 South of Girton 73,700 75,600 +3% 72,700 73,200 +1%

A428 Near Bourne Airfield 40,800 38,500 -6% 40,900 39,300 -4%

A1198 West of Hilton 13,300 15,100 +14% 11,500 12,400 +8%

A141 North of Huntingdon 25,700 22,100 -14% 29,400 28,300 -4%


2.5.10 Table 2.7 compares daily traffic flows on major routes in 2035 with and

without the scheme. The picture is similar to 2020, with CHARM3a forecasting slightly lower flows on the strategic routes than CHARM2. The impact of the scheme is also similar, although the scale of change is slightly lower in CHARM3a in most places.

2.5.11 The only locations where the impact of the scheme is forecast to increase by more than 10% as a result of CHARM3a is on the A1 to the north and south of the Brampton Hut Interchange, even though the forecast flows with the scheme are lower in CHARM3a than in CHARM2.


Table 2.7: Impact of the scheme on major routes in 2035

Location

CHARM2 CHARM3a

Without scheme

With scheme

% Change

Without scheme

With scheme

% Change

A14 West of A1 51,500 65,200 +27% 51,600 55,700 +8%

A14 Spur East of A1(M) 63,900 25,500 -60% 53,300 24,600 -54%

A14 Through Huntingdon 90,500 17,000 -81% 90,300 14,600 -84%

A14 Huntingdon Southern Bypass - 95,500 - 0 80,300 -

A14 Swavesey to Bar Hill 93,400 112,300 +20% 94,600 104,600 +11%

A14 Bar Hill to Girton 110,700 135,900 +23% 111,300 127,500 +15%

A14 Histon to Milton 86,600 104,900 +21% 85,800 97,400 +14%

A14 East of Milton 82,300 84,700 +3% 79,300 81,300 +3%

A1 North of Alconbury 97,100 93,300 -4% 81,800 83,600 +2%

A1 North of Brampton Hut 52,100 81,500 +56% 43,500 74,200 +71%

A1 South of Brampton Hut 50,100 92,000 +84% 45,700 86,900 +90%

A1 Near Buckden 53,500 54,600 +2% 52,000 53,300 +3%

M11 South of Girton 83,600 90,100 +8% 83,000 85,500 +3%

A428 Near Bourne Airfield 55,300 48,200 -13% 51,900 48,000 -8%

A1198 West of Hilton 19,400 20,200 +4% 14,200 15,100 +6%

A141 North of Huntingdon 26,500 25,500 -4% 29,500 28,900 -2%


2.6 Scheme impact on local roads 2.6.1 Traffic forecasts with and without the scheme have also been prepared for a

selection of local roads based on both CHARM2 and CHARM3a versions of the traffic model.

Without scheme demand

2.6.2 Table 2.8 compares traffic flows on the local roads in 2014, 2020 and 2035 without the scheme. The forecast growth in traffic is much more variable on local roads, with some routes showing little or no growth between 2014 and 2035, while there is significant growth forecast on others. This reflects that some routes are already operating close to capacity and therefore cannot accommodate additional traffic, while others have spare capacity and therefore become more attractive alternatives as general traffic levels grow.

2.6.3 Across all of the selected local roads in CHARM2, traffic levels are forecast to

grow by 9% between 2014 and 2020 and a further 15% by 2035. In CHARM3a, slightly lower growth is forecast between 2014 and 2020 at 7% but growth is similar between 2020 and 2035 at 14%.


Table 2.8: Forecast 2-way AADT flows on local roads without the scheme


2014 2020 2035 2014 2020 2035

Local Roads around Huntingdon

B1043 Ermine Street (through Great Stukeley)

10,900 8,200 11,400 10,800 8,600 11,700

B1090 Station Road (through Abbotts Ripton)

5,300 5,400 6,700 5,700 6,000 7,400

B1514 Hartford Road (south of A141)

15,500 17,100 19,200 16,200 17,000 18,800

B1044 The Avenue (north of Godmanchester)

15,400 17,300 21,100 15,300 15,800 18,500

B1514 Huntingdon Road (east of Brampton)

15,400 21,800 25,300 15,900 17,600 20,800

B1514 Buckden Road (south of Brampton)

9,100 10,700 11,000 9,700 10,500 11,200

B1514 Thrapston Road (north of Brampton)

7,300 8,600 10,200 7,500 6,800 7,500

Local Roads between Huntingdon and Cambridge

A1123 Houghton Road (through St Ives)

14,700 15,000 15,000 14,600 14,600 14,900

B1040 Somersham Road (north of St Ives)

10,000 10,700 12,500 10,400 11,100 12,500

A1123 Station Road (through Earith)

24,300 24,100 23,400 23,300 23,100 23,200

High Street (through Over) 2,200 2,200 2,300 2,200 2,200 2,300

High Street (through Swavesey) 500 600 900 500 600 900

B1050 Station Road (through Willingham)

11,300 12,800 14,300 11,100 12,700 13,600

B1050 Hatton’s Road (south of Longstanton)

13,900 16,100 19,500 13,800 16,200 19,200

B1040 Potton Road (north of Hilton)

7,400 8,600 10,000 6,700 7,700 8,800

Elsworth Road (though Conington) 900 1,200 3,500 800 1,300 2,500

High Street (through Knapwell) 1,100 1,600 4,700 1,000 1,800 3,800

High Street (through Boxworth) 2,300 2,600 3,300 2,300 2,700 3,400

Scotland Road (through Dry Drayton)

4,800 6,200 8,300 4,900 5,900 8,700

Local Roads around Cambridge

A603 Barton Road (east of M11) 13,300 14,400 17,100 13,700 14,100 17,400

A1303 Madingley Road (east of M11)

15,800 16,800 19,800 16,100 18,300 21,000


A1307 Huntingdon Road (south of A14 )

10,600 10,800 13,500 10,800 11,000 13,500

Cambridge Road (through Girton) 5,100 6,100 9,200 5,300 5,900 8,900

B1049 Bridge Road (through Impington)

18,900 19,700 21,100 18,900 20,900 23,900

B1049 Histon Road (south of A14) 16,200 21,600 24,900 16,400 22,100 26,400

A10 Ely Road (through Milton) 21,000 21,900 22,400 21,000 23,100 24,500

A1309 Milton Road (south of A14) 30,200 31,400 32,600 31,500 31,200 35,700

A10 Ely Road (past Waterbeach) 25,700 26,800 27,700 25,700 26,500 27,600


With scheme demand

2.6.4 Table 2.9 and Table 2.10 compare traffic flow forecasts for the local roads with and without the scheme in 2020 and 2035 respectively. The percentage changes in flow as a result of the scheme have again been colour-coded to aid interpretation of the results.

2.6.5 In general, the CHARM3a forecasts are similar to or lower than the CHARM2

forecasts, with the following exceptions: traffic flows on the local roads in the vicinity of Brampton are forecast to be higher with the scheme in CHARM3a but lower without the scheme, leading to some changes in the impacts of the scheme; and traffic flows on the B1514 Huntingdon Road between Brampton and Huntingdon, previously forecast to increase by 3% in CHARM2 are forecast to increase by 31% in CHARM3a. Although forecast flows with the scheme have risen by 700 vehicles per day, the main reason for this increased impact is a reduction in forecast flows using this route of 4,500 vehicles per day in the ‘without’ scheme scenario. The reduction in the forecast growth of External to External traffic, in both the ‘with’ and ‘without’ scheme scenarios, results in a reduction in forecast flow on the A14 and other strategic roads and, hence, shorter journey times at some times of the day. This results in some local trips reassigning to use the Strategic Road Network in preference to local roads. This is the reason for the reduction in flows in the ‘without’ scheme scenario and thus the 31% increase in traffic flow in CHARM3a.

2.6.6 A small increase in traffic flows with the scheme is also shown on Elsworth

Road, Conington in CHARM3a in 2035. Here a change of +8% in vehicles per day is shown in CHARM3a as a result of the scheme, rather than the reduction of 11% shown in CHARM2. There are two reasons for this. Firstly, absolute flows are reduced in both the with and without scheme scenarios compared to CHARM2, likely as a result of the reduction in External to External traffic, with shorter distance trips moving back to the Strategic Road Network; however the reduction in flow in the without scheme scenario is more pronounced than in the with scheme scenario. Secondly, different junction layouts are assumed between CHARM2 and CHARM3a: the de-trunked A14 in CHARM3a is retained as per current layout; however, in


CHARM2, the Conington junction was coded as an at-grade roundabout as per the scheme design at the time of coding. The reversion to the existing layout provides more attractive access to the de-trunked route, resulting in the small increases shown over the ‘without’ scheme model.

2.6.7 Elsewhere, the forecast impacts of the scheme are similar. The scale of impact is generally reduced on local roads between Huntingdon and Cambridge, with flows on most roads forecast to change by 10% or less. The scheme is forecast to have a much lower impact on Swavesey and Conington compared with the earlier CHARM2 forecasts, while there are small reductions in the impacts of the scheme on many other routes.

2.6.8 Around Cambridge, there is also limited change. The forecasts show an increase in the impact of the scheme on the A1307 Huntingdon Road and a reduction in the impact on Cambridge Road through Girton. This is due to a greater proportion of the traffic travelling to and from the village of Girton rerouting via the A1307 rather than using the local roads to the north.

Table 2.9: Impact of the scheme on local roads in 2020

Location

CHARM2 CHARM3a

Without scheme

With scheme

% Change

Without scheme

With scheme

% Change



8,200 8,500 +4% 8,600 8,400 -2%


5,400 5,800 +7% 6,000 6,100 +2%


17,100 14,000 -18% 17,000 14,500 -15%


17,300 9,500 -45% 15,800 6,700 -58%


21,800 22,500 +3% 17,600 23,100 +31%


10,700 8,500 -21% 10,500 9,700 -8%


8,600 3,400 -60% 6,800 4,000 -41%



15,000 14,200 -5% 14,600 13,900 -5%


10,700 10,900 +2% 11,100 11,100 0%


24,100 24,000 0% 23,100 22,800 -1%

High Street (through Over) 2,200 2,200 0% 2,200 2,200 0%


High Street (through Swavesey) 600 700 +17% 600 600 0%


12,800 13,200 +3% 12,700 13,000 +2%


16,100 17,500 +9% 16,200 17,600 +9%


8,600 9,300 +8% 7,700 7,900 +3%

Elsworth Road (though Conington) 1,200 1,400 +17% 1,300 1,400 +8%

High Street (through Knapwell) 1,600 1,400 -13% 1,800 1,400 -22%

High Street (through Boxworth) 2,600 2,300 -12% 2,700 2,500 -7%


6,200 6,900 +11% 5,900 6,500 +10%


A603 Barton Road (east of M11) 14,400 14,700 +2% 14,100 14,300 +1%


16,800 16,500 -2% 18,300 18,100 -1%


10,800 12,000 +11% 11,000 12,400 +13%

Cambridge Road (through Girton) 6,100 5,500 -10% 5,900 4,900 -17%


19,700 20,300 +3% 20,900 22,200 +6%

B1049 Histon Road (south of A14) 21,600 22,300 +3% 22,100 22,700 +3%

A10 Ely Road (through Milton) 21,900 21,800 0% 23,100 23,200 0%

A1309 Milton Road (south of A14) 31,400 30,900 -2% 31,200 31,400 +1%

A10 Ely Road (past Waterbeach) 26,800 27,100 +1% 26,500 26,700 +1%


Table 2.10: Impact of the scheme on local roads in 2035

Location

CHARM2 CHARM3a

Without scheme

With scheme

% Change

Without scheme

With scheme

% Change



11,400 11,800 +4% 11,700 11,300 -3%


6,700 7,000 +4% 7,400 7,200 -3%


19,200 16,000 -17% 18,800 16,400 -13%


21,100 12,100 -43% 18,500 8,700 -53%



25,300 24,600 -3% 20,800 25,300 +22%


11,000 8,700 -21% 11,200 9,600 -14%


10,200 3,900 -62% 7,500 4,300 -43%



15,000 14,300 -5% 14,900 14,100 -5%


12,500 12,600 +1% 12,500 12,600 +1%


23,400 22,500 -4% 23,200 22,600 -3%

High Street (through Over) 2,300 2,200 -4% 2,300 2,100 -9%

High Street (through Swavesey) 900 900 0% 900 900 0%


14,300 16,200 +13% 13,600 16,200 +19%


19,500 16,200 -17% 19,200 16,600 -14%


10,000 10,000 0% 8,800 9,200 +5%

Elsworth Road (though Conington) 3,500 3,100 -11% 2,500 2,700 +8%

High Street (through Knapwell) 4,700 3,200 -32% 3,800 3,200 -16%

High Street (through Boxworth) 3,300 3,100 -6% 3,400 3,300 -3%


8,300 11,200 +35% 8,700 11,100 +28%


A603 Barton Road (east of M11) 17,100 16,900 -1% 17,400 17,000 -2%


19,800 18,200 -8% 21,000 20,000 -5%


13,500 16,700 +24% 13,500 17,400 +29%

Cambridge Road (through Girton) 9,200 7,800 -15% 8,900 6,900 -22%


21,100 20,300 -4% 23,900 24,000 0%

B1049 Histon Road (south of A14) 24,900 25,400 +2% 26,400 26,400 0%

A10 Ely Road (through Milton) 22,400 22,500 0% 24,500 24,600 0%

A1309 Milton Road (south of A14) 32,600 34,500 +6% 35,700 35,600 0%

A10 Ely Road (past Waterbeach) 27,700 27,700 0% 27,600 27,600 0%



2.7 Scheme impact on A14 junctions 2.7.1 Table 2.11 compares forecast daily traffic flows on A14 junctions in 2014,

2020 and 2035 without the scheme. Forecasts are presented for all major junctions from Junction 21 (Brampton Hut) to Junction 33 (Milton) for both CHARM2 and CHARM3a. This comparison shows that all of these junctions are forecast to get busier as traffic levels increase up to 2035.

2.7.2 The rate of traffic growth is generally slightly higher in CHARM3a than in CHARM2. These higher flows are a result of the lower External to External growth assumptions in CHARM3a, resulting in greater capacity on the A14 and other strategic routes for local traffic that was forecast to use local roads in CHARM2. As a result, there is an increase in the volume of local traffic entering and exiting the A14 at these junctions leading to increased daily flows at the junctions.

Table 2.11: Forecast AADT flows on A14 junctions without the scheme

Junction CHARM2 CHARM3a

2014 2020 2035 2014 2020 2035

Brampton Hut (J21) 52,700 55,400 62,300 52,700 57,800 64,100

Racecourse (J22) 8,600 9,400 10,300 8,600 9,000 9,500

Spittals (J23) 63,100 59,700 62,100 63,100 68,400 72,900

Godmanchester (J24) 27,100 29,500 37,600 27,100 29,200 35,300

Hemingfords (J25) 3,400 3,500 4,000 3,400 3,500 3,700

A1096 (J26) 21,200 22,300 23,200 21,200 22,900 25,000

Fenstanton (J27) 9,100 10,100 13,200 9,100 9,400 11,400

Swavesey (J28) 10,900 12,400 13,100 10,900 12,800 14,100

Bar Hill (J29) 27,000 30,000 35,400 27,000 30,300 35,400

Histon (J32) 38,000 45,700 54,400 38,000 46,300 55,300

Milton (J33) 48,000 52,100 52,200 48,000 51,700 57,300


2.7.3 Table 2.12 and Table 2.13 compare the impact of the A14 scheme on A14

junctions in 2020 and 2035 respectively. Both CHARM2 and CHARM3a show a similar picture, with the junctions at the western end of the scheme around Huntingdon getting significantly quieter, while the junctions at the eastern end of the scheme get slightly busier. The most significant increases in traffic are at the Swavesey Interchange (Junction 28), which reflects that it changes from a local access junction without the scheme to a major interchange with the scheme. The proposed design of this junction takes account of its increased importance and the consequential increase in traffic flows. A small increase of 8% is also shown at Bar Hill junction (Junction 29); this is as a result of changes in trip loading at Northstowe, providing better access/egress from the Phase 2 development.


Table 2.12: Impact of the scheme on A14 junctions in 2020

Junction

CHARM2 CHARM3a

2014 2020 %

Change 2014 2020

% Change

Brampton Hut (J21) 55,400 25,600 -54% 57,800 28,900 -50%

Racecourse (J22) 9,400 6,000 -36% 9,000 6,000 -33%

Spittals (J23) 59,700 30,200 -49% 68,400 31,000 -55%

Godmanchester (J24) 29,500 23,700 -20% 29,200 24,400 -16%

Hemingfords (J25) 3,500 3,700 +6% 3,500 3,600 +3%

A1096 (J26) 22,300 25,900 +16% 22,900 25,900 +13%

Fenstanton (J27) 10,100 8,200 -19% 9,400 7,800 -17%

Swavesey (J28) 12,400 39,300 +217% 12,800 38,200 +198%

Bar Hill (J29) 30,000 32,400 +8% 30,300 33,100 +9%

Histon (J32) 45,700 48,500 +6% 46,300 49,300 +6%

Milton (J33) 52,100 53,100 +2% 51,700 53,200 +3%

Units: vehicles per day, rounded to the nearest 100. Table 2.13: Impact of the scheme on A14 junctions in 2035

Junction

CHARM2 CHARM3a

2014 2020 %

Change 2014 2020

% Change

Brampton Hut (J21) 62,300 27,200 -56% 64,100 32,200 -50%

Racecourse (J22) 10,300 7,300 -29% 9,500 7,200 -24%

Spittals (J23) 62,100 33,000 -47% 72,900 33,000 -55%

Godmanchester (J24) 37,600 28,100 -25% 35,300 27,200 -23%

Hemingfords (J25) 4,000 4,100 +2% 3,700 4,000 +8%

A1096 (J26) 23,200 29,300 +26% 25,000 29,400 +18%

Fenstanton (J27) 13,200 9,400 -29% 11,400 9,200 -19%

Swavesey (J28) 13,100 45,800 +250% 14,100 46,000 +226%

Bar Hill (J29) 35,400 44,600 +26% 35,400 47,400 +34%

Histon (J32) 54,400 53,900 -1% 55,300 58,300 +5%

Milton (J33) 52,200 57,600 +10% 57,300 59,500 +4%


2.8 Scheme impact on Cambridge 2.8.1 Further analysis, over and above that reported in the Transport Assessment

(document reference 7.2), has been undertaken to assess the impact of the scheme on Cambridge. Forecast peak hour traffic flows have been extracted for all of the radial roads in to the city in 2014, 2020 and 2035, with further


detail provided for the four radial routes on the north-west side of the city that are most affected by the scheme.

Impact on radial routes

2.8.2 Table 2.14 compares peak hour flows on the radial routes in 2014, 2020 and 2035 without the scheme. The CHARM2 forecasts indicate that traffic entering and exiting the city in the AM peak hour is expected to grow by around 10% between 2014 and 2020 with a further 12% growth occurring between 2020 and 2035. Slightly higher traffic growth is forecast in the PM peak hour, with traffic levels expected to increase by 11% between 2014 and 2020 and by 13% between 2020 and 2035. CHARM3a predicts a similar level of growth between 2014 and 2020 in the AM peak hour, but the growth rates between 2014 and 2020 in the PM peak hour and in both peak hours in 2035 are slightly higher than CHARM2 (at around 16-17%).

2.8.3 Highways England’s growth forecasts take account of committed and planned

development in Cambridge, but do not include allowance for any transport policy measures that may be introduced to manage future traffic growth. Annual monitoring of traffic on the Cambridge radial routes indicates that traffic flows have not changed substantially over the last 10 years. This is in part due to the global recession but also a result of the demand management measures that have been implemented over this period. It is expected that further measures would be introduced to manage future traffic growth. However, it is not possible to model their effects as details of these interventions are not currently known. As such these traffic forecasts represent a worst case assessment of likely future growth in the city.

2.8.4 The planned developments in Cambridge are mainly focussed on the fringes

of the city. Consequently it is the radial routes around the edge of the city where the impacts of these developments are most apparent. Traffic growth in central Cambridge is forecast to be substantially lower due to a combination of a lack of spare capacity and a limited number of planned developments.

Table 2.14: Forecast 2-way peak hour flows on Cambridge radials without the scheme


2014 2020 2035 2014 2020 2035

AM Peak hour

Histon Road 2,850 3,450 3,900 2,850 3,500 4,200

Milton Road 2,550 2,900 3,050 2,550 2,800 3,150

Horningsea Road 1,500 1,650 1,350 1,450 1,550 1,400

Newmarket Road 2,200 1,450 2,100 2,200 1,300 2,000

Wilbraham Road 250 700 1,100 300 850 1,050

Balsham Road 1,050 1,250 1,250 1,100 1,300 1,300

Babraham Road 1,700 1,650 1,900 1,750 1,800 2,050


Shelford Road 600 950 1,150 650 1,050 1,300

Hauxton Way 2,400 2,750 3,050 2,350 3,050 3,350

Barton Road 1,100 1,150 1,300 1,100 1,050 1,300

Madingley Road 1,300 1,300 1,350 1,300 1,300 1,450

Huntingdon Road 1,200 1,350 1,550 1,250 1,300 1,600

Total 18,700 20,550 23,050 18,850 20,850 24,150

PM Peak hour

Histon Road 2,600 3,300 3,600 2,650 3,650 4,200

Milton Road 2,350 3,200 3,100 2,350 3,150 3,600

Horningsea Road 1,600 1,800 1,950 1,700 1,800 2,250

Newmarket Road 2,350 1,950 2,350 2,300 2,100 2,250

Wilbraham Road 350 700 1,100 200 750 1,300

Balsham Road 1,050 1,300 1,500 1,000 1,500 1,800

Babraham Road 1,800 1,750 2,100 1,900 1,850 2,250

Shelford Road 800 1,150 1,350 850 1,150 1,450

Hauxton Way 2,250 2,450 2,800 2,250 2,700 3,000

Barton Road 1,250 1,100 1,150 1,250 1,000 1,100

Madingley Road 1,700 1,700 2,000 1,700 2,050 2,350

Huntingdon Road 1,600 1,500 1,700 1,600 1,500 1,600

Total 19,700 21,900 24,700 19,750 23,200 27,150

Units: vehicles per hour, rounded to the nearest 50.

2.8.5 Table 2.15 and Table 2.16 assess the impact of the scheme on the

Cambridge radial roads in 2020 and 2035. This shows that flows on most of the radials changes by less than 5% as a result of the scheme, with similar impacts forecast by both CHARM2 and CHARM3a. The biggest changes in flow as a result of the scheme are on Milton Road, where flows are forecast to fall by approximately 13% in the AM peak hour and by over 40% in the PM peak hour. This is due to the additional capacity created by the scheme on the Cambridge Northern Bypass, which allows traffic from the east to access Cambridge via the most appropriate radial route based on its final destination. Without the scheme, this traffic tends to leave the A14 at the Milton junction (Junction 33) to avoid congestion on the A14.

2.8.6 Flows on Huntingdon Road are forecast to increase by 25% in the PM peak

hour in 2035 as a result of the scheme. This is primarily a result of traffic accessing the village of Girton rerouting via Huntingdon Road rather than using local roads to the north of the village. This route is forecast to be more attractive as a result of the scheme, in part due to the improved connectivity offered by the Local Access Road and also due to the closure of the slip roads at the Dry Drayton junction (Junction 30) which would otherwise restrict access to the village of Girton from the A14. There is no significant change in


traffic flow on Huntingdon Road south of the junction with Girton Road in the ‘with’ scheme model. This demonstrates that the rerouting noted above is primarily concerned with traffic accessing the village of Girton. There is a greater increase south of the junction in CHARM3a than CHARM2. This is in part due to a reduction in flows in the without scheme model.

Table 2.15: Impact of the scheme on Cambridge radials in 2020

Location

CHARM2 CHARM3a

Without scheme

With scheme

% Change

Without scheme

With scheme

% Change

AM Peak hour

Histon Road 3,450 3,450 0% 3,500 3,650 +4%

Milton Road 2,900 2,550 -12% 2,800 2,450 -13%

Horningsea Road 1,650 1,700 +3% 1,550 1,550 0%

Newmarket Road 1,450 1,400 -3% 1,300 1,300 0%

Wilbraham Road 700 700 0% 850 850 0%

Balsham Road 1,250 1,250 0% 1,300 1,300 0%

Babraham Road 1,650 1,650 0% 1,800 1,750 -3%

Shelford Road 950 950 0% 1,050 1,050 0%

Hauxton Way 2,750 2,700 -2% 3,050 2,950 -3%

Barton Road 1,150 1,200 +4% 1,050 1,050 0%

Madingley Road 1,300 1,300 0% 1,300 1,350 +4%

Huntingdon Road 1,350 1,400 +4% 1,300 1,350 +4%

Total 20,550 20,250 -1% 20,850 20,600 -1%

PM Peak hour

Histon Road 3,300 3,450 +5% 3,650 3,750 +3%

Milton Road 3,200 1,900 -41% 3,150 1,800 -43%

Horningsea Road 1,800 1,900 +6% 1,800 1,800 0%

Newmarket Road 1,950 2,000 +3% 2,100 2,150 +2%

Wilbraham Road 700 700 0% 750 800 +7%

Balsham Road 1,300 1,300 0% 1,500 1,500 0%

Babraham Road 1,750 1,750 0% 1,850 1,850 0%

Shelford Road 1,150 1,100 -4% 1,150 1,150 0%

Hauxton Way 2,450 2,450 0% 2,700 2,700 0%

Barton Road 1,100 1,100 0% 1,000 1,000 0%

Madingley Road 1,700 1,600 -6% 2,050 2,050 0%

Huntingdon Road 1,500 1,600 +7% 1,500 1,550 +3%

Total 21,900 20,850 -5% 23,200 22,100 -5%



Table 2.16: Impact of the scheme on Cambridge radials in 2035

Location

CHARM2 CHARM3a

Without scheme

With scheme

% Change

Without scheme

With scheme

% Change

AM Peak hour

Histon Road 3,900 3,850 -1% 4,200 4,400 +5%

Milton Road 3,050 2,700 -11% 3,150 2,700 -14%

Horningsea Road 1,350 1,400 +4% 1,400 1,400 0%

Newmarket Road 2,100 2,100 0% 2,000 2,000 0%

Wilbraham Road 1,100 1,100 0% 1,050 1,100 +5%

Balsham Road 1,250 1,300 +4% 1,300 1,300 0%

Babraham Road 1,900 1,950 +3% 2,050 2,050 0%

Shelford Road 1,150 1,200 +4% 1,300 1,300 0%

Hauxton Way 3,050 3,050 0% 3,350 3,300 -1%

Barton Road 1,300 1,300 0% 1,300 1,300 0%

Madingley Road 1,350 1,300 -4% 1,450 1,400 -3%

Huntingdon Road 1,550 1,600 +3% 1,600 1,600 0%

Total 23,050 22,850 -1% 24,150 23,850 -1%

PM Peak hour

Histon Road 3,600 3,400 -6% 4,200 4,250 +1%

Milton Road 3,100 2,600 -16% 3,600 2,050 -43%

Horningsea Road 1,950 1,850 -5% 2,250 2,200 -2%

Newmarket Road 2,350 2,350 0% 2,250 2,250 0%

Wilbraham Road 1,100 1,100 0% 1,300 1,350 +4%

Balsham Road 1,500 1,500 0% 1,800 1,750 -3%

Babraham Road 2,100 2,050 -2% 2,250 2,200 -2%

Shelford Road 1,350 1,300 -4% 1,450 1,400 -3%

Hauxton Way 2,800 2,800 0% 3,000 3,000 0%

Barton Road 1,150 1,100 -4% 1,100 1,050 -5%

Madingley Road 2,000 1,850 -8% 2,350 2,200 -6%

Huntingdon Road 1,700 1,850 +9% 1,600 2,000 +25%

Total 24,700 23,750 -4% 27,150 25,700 -5%


Further detail on impact on north-west radials

2.8.7 The impacts of the scheme are focussed on the radial routes closest to the A14 (A1303 Madingley Road, A1307 Huntingdon Road, B1049 Histon Road and A1309 Milton Road). Table 2.17 summarises the forecast peak hour


traffic flows on these roads in 2014, 2020 and 2035 without the scheme. Traffic flows are reported at two locations on each road; an outer site which corresponds to the radial routes reported above; and an inner site which reflects traffic flows further into the city.

2.8.8 In general, CHARM3a shows higher growth than CHARM2. This is due to the

reduction in External to External traffic growth, which creates additional capacity for local traffic associated with the planned developments around the city fringe and in the surrounding area.

2.8.9 The biggest growth in traffic is forecast to occur on Histon Road, where

CHARM3a indicates that traffic will grow by 47% in the AM peak hour and by 58% in the PM peak hour between 2014 and 2035. This increase is the result of additional traffic generated by the proposed Darwin Green development and also reflects an increasing propensity for some traffic on the A428 to use Histon Road rather than Madingley Road to access the city centre due to the additional capacity created on the A14 by Highways England’s Girton to Histon pinch-point scheme. It is this latter effect that is the cause of the significant growth that is forecast to occur on the Histon Road inner site.

2.8.10 Despite the transfer of traffic from the A428 onto Histon Road, traffic flows on Madingley Road outer site are forecast to grow by 12% in the AM peak hour and by 38% in the PM peak hour between 2014 and 2035. This growth is a result of additional car trips on the A428 generated by the Cambourne West and Bourn Airfield developments to the west of the city and also traffic associated with the West Cambridge and North-West Cambridge developments on the fringe. Much lower growth is evident on this corridor further into the city, reflecting the fact that much of the growth is absorbed by the park-and-ride site or leaves the network before it reaches the city centre.

2.8.11 Over the same period, traffic flows on Huntingdon Road outer site are forecast

to increase by 28% in the AM peak hour. However, no growth is forecast in the PM peak hour. The growth in the AM peak hour is in part due to the additional traffic generated by the North-West Cambridge development, but also as a result of more long-distance traffic using this route to access the city centre. However, in the PM peak hour, this development traffic growth is offset by a reduction in long-distance traffic using this route to access the city centre.

2.8.12 Traffic on Milton Road outer site is forecast to grow by 24% in the AM peak hour and by 53% in the PM peak hour. Much of this growth is attributable to the Cambridge northern fringe developments and also the Waterbeach development to the north. However, it also reflects that a greater proportion of traffic on the A14 to the east chooses to use this corridor to access the city centre to avoid congestion on the A14 Cambridge Northern Bypass and other radial routes. At the inner site, the majority of the development traffic has dispersed, and consequently much lower levels of growth are forecast here.


Table 2.17: Forecast 2-way peak hour flows on north-west Cambridge radials without the scheme


2014 2020 2035 2014 2020 2035

AM Peak hour

Madingley Road (outer) 1,300 1,300 1,350 1,300 1,300 1,450

Madingley Road (inner) 1,400 1,200 1,300 1,450 1,200 1,350

Huntingdon Road (outer) 1,200 1,350 1,550 1,250 1,300 1,600

Huntingdon Road (inner) 1,400 1,600 1,800 1,450 1,550 1,850

Histon Road (outer) 2,850 3,450 3,900 2,850 3,500 4,200

Histon Road (inner) 1,000 1,350 1,550 1,000 1,300 1,600

Milton Road (outer) 2,550 2,900 3,050 2,550 2,800 3,150

Milton Road (inner) 700 650 800 750 700 850

PM Peak hour

Madingley Road (outer) 1,700 1,700 2,000 1,700 2,050 2,350

Madingley Road (inner) 1,750 1,600 1,750 1,700 1,700 1,750

Huntingdon Road (outer) 1,600 1,500 1,700 1,600 1,500 1,600

Huntingdon Road (inner) 1,650 1,600 1,800 1,600 1,600 1,750

Histon Road (outer) 2,600 3,300 3,600 2,650 3,650 4,200

Histon Road (inner) 1,000 1,200 1,450 850 1,200 1,400

Milton Road (outer) 2,350 3,200 3,100 2,350 3,150 3,600

Milton Road (inner) 950 900 850 950 900 1,000


2.8.13 Table 2.18 and Table 2.19 summarise the impact of the A14 scheme on the

north-west Cambridge radial roads in 2020 and 2035 respectively. These show that the scheme is forecast to have limited impact on most of these roads, with peak hour flows forecast to change by less than 5%. The main changes are on the Milton Road and Huntingdon Road outer sites, as discussed. The changes to flows at the Milton Road inner site in CHARM2 are no longer apparent in CHARM3a, indicating that traffic patterns are more stable in CHARM3a.

Table 2.18: Impact of the scheme on north-west Cambridge radials in 2020

Location

CHARM2 CHARM3a

Without scheme

With scheme

% Change

Without scheme

With scheme

% Change

AM Peak hour

Madingley Road (outer) 1,300 1,300 0% 1,300 1,350 +4%

Madingley Road (inner) 1,200 1,150 -4% 1,200 1,150 -4%


Huntingdon Road (outer) 1,350 1,400 +4% 1,300 1,350 +4%

Huntingdon Road (inner) 1,600 1,600 0% 1,550 1,550 0%

Histon Road (outer) 3,450 3,450 0% 3,500 3,650 +4%

Histon Road (inner) 1,350 1,350 0% 1,300 1,300 0%

Milton Road (outer) 2,900 2,550 -12% 2,800 2,450 -13%

Milton Road (inner) 650 650 0% 700 700 0%

PM Peak hour

Madingley Road (outer) 1,700 1,600 -6% 2,050 2,050 0%

Madingley Road (inner) 1,600 1,550 -3% 1,700 1,700 0%


Huntingdon Road (inner) 1,600 1,600 0% 1,600 1,550 -3%

Histon Road (outer) 3,300 3,450 +5% 3,650 3,750 +3%



Milton Road (inner) 900 700 -22% 900 850 -6%

Units: vehicles per hour, rounded to the nearest 50. Table 2.19: Impact of the scheme on north-west Cambridge radials in 2035

Location

CHARM2 CHARM3a

Without scheme

With scheme

% Change

Without scheme

With scheme

% Change

AM Peak hour

Madingley Road (outer) 1,350 1,300 -4% 1,450 1,400 -3%

Madingley Road (inner) 1,300 1,250 -4% 1,350 1,300 -4%

Huntingdon Road (outer) 1,550 1,600 +3% 1,600 1,600 0%

Huntingdon Road (inner) 1,800 1,750 -3% 1,850 1,800 -3%

Histon Road (outer) 3,900 3,850 -1% 4,200 4,400 +5%



Milton Road (inner) 800 800 0% 850 850 0%

PM Peak hour

Madingley Road (outer) 2,000 1,850 -8% 2,350 2,200 -6%

Madingley Road (inner) 1,750 1,800 +3% 1,750 1,750 0%


Huntingdon Road (inner) 1,800 1,800 0% 1,750 1,800 +3%

Histon Road (outer) 3,600 3,400 -6% 4,200 4,250 +1%




Milton Road (inner) 850 1,100 +29% 1,000 1,000 0%


2.9 Scheme impact on Huntingdon 2.9.1 Further analysis has also been undertaken to assess the impact of the

scheme on Huntingdon. Forecast peak hour traffic flows have been extracted for all of the radial roads in to the town and a selection of roads in the town centre in 2014, 2020 and 2035.

Impact on radial routes

2.9.2 Table 2.20 summarises forecast flows on the radial routes around Huntingdon in 2014, 2020 and 2035 without the scheme. Across all routes CHARM3a forecasts that traffic will grow by 5% between 2014 and 2020 with a further 10% growth between 2020 and 2035 in both peak hours. On most routes traffic is forecast to increase by around 10% by 2020 and by around 30-40% by 2035. However, on the A141 and Ermine Street to the north-west of the town there is a reduction in flow in 2020 and limited change in 2035 as some traffic reroutes to avoid congestion around the Spittals Interchange.

Table 2.20: Forecast 2-way peak hour flows on Huntingdon radials without the scheme


2014 2020 2035 2014 2020 2035

AM Peak hour

Kings Ripton Road 400 450 550 450 500 600

A141 (east) 1,400 1,500 1,850 1,500 1,600 1,800

A1123 350 350 500 300 350 500

Huntingdon Town Bridge 1,500 1,600 1,850 1,450 1,500 1,750

A14 (de-trunked) 5,250 5,700 6,250 5,300 5,850 6,350

Brampton Road 1,650 1,800 1,850 1,650 1,550 1,700

Views Common Link - - - - - -

A141 (west) 2,400 2,200 2,100 2,350 2,500 2,350

Ermine Street 1,000 800 950 1,000 850 1,050

Total 13,950 14,400 15,900 14,000 14,700 16,100

PM Peak hour

Kings Ripton Road 500 500 550 500 500 600

A141 (east) 1,600 1,800 2,050 1,650 1,850 2,150

A1123 350 350 450 300 300 400



A14 (de-trunked) 5,800 6,150 6,600 5,750 6,350 6,950

Brampton Road 1,600 2,100 2,300 1,550 1,750 1,850


A141 (west) 2,550 2,450 2,500 2,600 2,600 2,550

Ermine Street 1,200 950 1,300 1,150 950 1,300

Total 15,250 16,100 17,850 15,100 15,900 17,550


2.9.3 Table 2.21 and Table 2.22 summarise the impact of the scheme on the radial

routes around Huntingdon in 2020 and 2035 respectively. In general both CHARM2 and CHARM3a predict similar impacts, with limited change in the forecast flows on the routes to the north and west of the town and a marked reduction in flow on the detrunked A14 and Huntingdon Town Bridge.

2.9.4 The main differences between CHARM3a and CHARM2 are on the A1123

and Brampton Road. On the A1123 the impact of the scheme is forecast to be lower in the AM peak hour in CHARM3a but higher in the PM peak hour. However, the absolute change in forecasts flows are small (less than 50 vehicles per hour), which is not indicative of a material impact. On Brampton Road both models forecast a reduction in flows; however the magnitude of that reduction is much smaller in CHARM3a. This change is mainly due to a reduction in the volume of traffic forecast to use Brampton Road without the scheme. This is a result of the lower External to External growth assumptions in CHARM3a, which means that there is more capacity on the Strategic Road Network for local traffic than there is in CHARM2. Consequently, some traffic that is forecast to use Brampton Road in CHARM2 is predicted to transfer on to the A14 in CHARM3a. Other large percentage changes represent small numbers of trips and are not considered to be significant.

Table 2.21: Impact of the scheme on Huntingdon radials in 2020

Location

CHARM2 CHARM3a

Without scheme

With scheme

% Change

Without scheme

With scheme

% Change

AM Peak hour

Kings Ripton Road 450 450 0% 500 500 0%

A141 (east) 1,500 1,500 0% 1,600 1,550 -3%

A1123 350 400 +14% 350 350 0%

Huntingdon Town Bridge 1,600 1,000 -38% 1,500 750 -50%

A14 (de-trunked) 5,700 2,200 -61% 5,850 2,500 -57%

Brampton Road 1,800 1,300 -28% 1,550 1,450 -6%

Views Common Link - 1,150 - - 1,050 -

A141 (west) 2,200 2,300 +5% 2,500 2,400 -4%

Ermine Street 800 750 -6% 850 700 -18%


PM Peak hour

Kings Ripton Road 500 500 0% 500 550 +10%

A141 (east) 1,800 1,750 -3% 1,850 1,750 -5%

A1123 350 350 0% 300 350 +17%


A14 (de-trunked) 6,150 2,250 -63% 6,350 2,700 -57%

Brampton Road 2,100 1,400 -33% 1,750 1,600 -9%


A141 (west) 2,450 2,450 0% 2,600 2,650 +2%

Ermine Street 950 1,000 +5% 950 1,000 +5%


Table 2.22: Impact of the scheme on Huntingdon radials in 2035

Location

CHARM2 CHARM3a

Without scheme

With scheme

% Change

Without scheme

With scheme

% Change

AM Peak hour

Kings Ripton Road 550 550 0% 600 600 0%

A141 (east) 1,850 1,800 -3% 1,800 1,850 3%

A1123 500 550 +10% 500 550 +10%


A14 (de-trunked) 6,250 2,250 -64% 6,350 2,700 -57%

Brampton Road 1,850 1,200 -35% 1,700 1,350 -21%


A141 (west) 2,100 2,200 +5% 2,350 2,250 -4%

Ermine Street 950 950 0% 1,050 950 -10%

PM Peak hour

Kings Ripton Road 550 600 +9% 600 650 +8%

A141 (east) 2,050 1,950 -5% 2,150 2,000 -7%

A1123 450 500 +11% 400 450 +13%

Huntingdon Town Bridge 2,100 1,400 -33% 1,750 1,050 -40%

A14 (de-trunked) 6,600 2,450 -63% 6,950 2,750 -60%

Brampton Road 2,300 1,300 -43% 1,850 1,550 -16%


A141 (west) 2,500 2,450 -2% 2,550 2,500 -2%

Ermine Street 1,300 1,300 0% 1,300 1,200 -8%



Impact on Huntingdon town centre

2.9.5 Table 2.23 summarises forecast flows on a selection of roads in Huntingdon town centre in 2014, 2020 and 2035 without the scheme. There is significant variation in the growth on these roads, with flows on Stukeley Road and St Peters Road to the north of the town centre forecast to increase significantly, while flows on Hartford Road, Brampton Road and the town centre ring road are only forecast to experience moderate traffic growth in the period to 2035. This reflects the fact that some routes are already operating close to capacity in the peak hours and therefore there is limited opportunity for further traffic growth. Other routes, although busy, are still able to accommodate some further traffic demand. The changes are also reflective of the rerouting of traffic to avoid congestion around the Spittals Interchange (Junction 23), with some traffic utilising local roads to the north of the town instead.

Table 2.23: Forecast 2-way peak hour flows in central Huntingdon without the scheme


2014 2020 2035 2014 2020 2035

AM Peak hour

St Peters Road 500 800 900 550 800 950

Arbury Road 200 250 250 200 200 250

Ring Road (north) 850 850 950 900 850 900

Hartford Road 1,400 1,450 1,550 1,450 1,550 1,600


Ring Road (south) 1,150 1,100 1,300 1,150 1,050 1,200

Brampton Road 1,650 1,800 1,850 1,650 1,550 1,700


Edison Bell Way - 700 750 - 500 650

Stukeley Road 800 1,100 1,400 800 1,100 1,350

PM Peak hour

St Peters Road 600 900 1,000 600 800 1,000

Arbury Road 200 250 450 200 250 300

Ring Road (north) 1,350 1,500 1,550 1,350 1,400 1,500

Hartford Road 1,650 1,750 1,850 1,700 1,750 1,800


Ring Road (south) 1,050 1,050 1,350 1,000 950 1,150

Brampton Road 1,600 2,100 2,300 1,550 1,750 1,850


Edison Bell Way - 800 1,050 - 500 650

Stukeley Road 950 1,150 1,600 950 1,150 1,550



2.9.6 Table 2.24 and Table 2.25 summarise the impact of the scheme on

Huntingdon town centre roads in 2020 and 2035 respectively. Once again both models show a similar pattern of impact, with the main differences being on Brampton Road (as discussed previously) and Edison Bell Way. On Edison Bell Way there is little difference in the forecast flows with the scheme, but a substantial reduction in flows using this route without the scheme. This is due to more traffic being assigned to the A14 to access the areas to the north and west of the town centre in CHARM3a. A large percentage change is forecast on Arbury Road in the 2020 AM peak hour and the 2035 PM peak hour. However, closer examination of the forecasts indicates that absolute changes in flow are very small and not indicative of a material change in traffic levels.

Table 2.24: Impact of peak hour flows in central Huntingdon without the scheme

Location

CHARM2 CHARM3a

Without scheme

With scheme

% Change

Without scheme

With scheme

% Change

AM Peak hour

St Peters Road 800 950 +19% 800 950 +19%

Arbury Road 250 200 -20% 200 250 +25%

Ring Road (north) 850 700 -18% 850 700 -18%

Hartford Road 1,450 1,300 -10% 1,550 1,350 -13%


Ring Road (south) 1,100 650 -41% 1,050 800 -24%

Brampton Road 1,800 1,300 -28% 1,550 1,450 -6%


Edison Bell Way 700 800 +14% 500 750 +50%

Stukeley Road 1,100 1,300 +18% 1,100 1,350 +23%

PM Peak hour

St Peters Road 900 1,000 +11% 800 1,050 +31%

Arbury Road 250 250 0% 250 250 0%

Ring Road (north) 1,500 1,200 -20% 1,400 1,250 -11%

Hartford Road 1,750 1,550 -11% 1,750 1,600 -9%


Ring Road (south) 1,050 450 -57% 950 650 -32%

Brampton Road 2,100 1,400 -33% 1,750 1,600 -9%


Edison Bell Way 800 950 +19% 500 850 +70%

Stukeley Road 1,150 1,450 +26% 1,150 1,500 +30%



Table 2.25: Impact of the scheme on central Huntingdon in 2035

Location

CHARM2 CHARM3a

Without scheme

With scheme

% Change

Without scheme

With scheme

% Change

AM Peak hour

St Peters Road 900 1,050 +17% 950 1,100 +16%

Arbury Road 250 250 0% 250 250 0%

Ring Road (north) 950 700 -26% 900 800 -11%

Hartford Road 1,550 1,500 -3% 1,600 1,550 -3%


Ring Road (south) 1,300 650 -50% 1,200 900 -25%

Brampton Road 1,850 1,200 -35% 1,700 1,350 -21%


Edison Bell Way 750 900 +20% 650 900 +38%

Stukeley Road 1,400 1,500 +7% 1,350 1,550 +15%

PM Peak hour

St Peters Road 1,000 1,200 +20% 1,000 1,200 +20%

Arbury Road 450 350 -22% 300 350 +17%

Ring Road (north) 1,550 1,250 -19% 1,500 1,350 -10%

Hartford Road 1,850 1,750 -5% 1,800 1,750 -3%

Huntingdon Town Bridge 2,100 1,400 -33% 1,750 1,050 -40%

Ring Road (south) 1,350 700 -48% 1,150 800 -30%

Brampton Road 2,300 1,300 -43% 1,850 1,550 -16%


Edison Bell Way 1,050 1,050 0% 650 1,000 +54%

Stukeley Road 1,600 1,700 +6% 1,550 1,650 +6%



3 Operational assessment

3.1 Introduction 3.1.1 The Transport Assessment submitted with the DCO application in December

2014 (document reference 7.2) included the results of operational assessments on junctions along the route of the scheme between Ellington (Junction 20) and Milton (Junction 33) in 2020 (the opening year) and 2035 (a future forecast year).

3.1.2 This section of the Traffic Modelling Update Report provides an update on the operational assessment of the scheme in response to CHARM3a traffic forecasts.

Method of assessment

3.1.3 The method of assessment is the same as that used in the Transport

Assessment (document reference 7.2, section 7.7.8). The performance of the junctions has been assessed by considering the ‘ratio to flow capacity’ (RFC) or ‘degree of saturation’ (DoS) for each of the approach arms. An RFC / DoS value of 85% or below (highlighted in green) indicates that the arm is operating within design capacity. An RFC / DoS value of 85% to 100% (highlighted in amber) indicates that the approach is operating above design capacity but within theoretical capacity, while an RFC / DoS value of 100% or more (highlighted in red) indicates that the arm is operating above theoretical capacity and queuing and delays may occur.

3.2 Junction operational assessments 3.2.1 As noted in the Transport Assessment (document reference 7.2) the majority

of junctions along the length of the scheme would be entirely new junctions, or existing junctions that would be substantially remodelled or removed as part of the scheme.

3.2.2 Consequently ‘Do-Minimum’, that is, ‘without’ scheme operational assessments have only been carried out for those junctions that would be substantially unaltered by the scheme proposals. These junctions are:

• Swavesey junction – Services roundabout;

• Bar Hill junction – South roundabout;

• Histon junction;

• Milton junction;

• Hinchingbrooke Park Road / Views Common junction;

• Brampton Road / Underpass junction;

• Brampton Road / Hinchingbrooke Park Road junction;

• Brampton Road / Edison Bell Way junction;


• Ermine Street / Edison Bell Way junction; and

• North West Cambridge junction.

3.2.3 Table 3.1 and Table 3.2 summarise the average RFC / DoS on the worst performing arm and the average delay per vehicle for each junction in 2020 and 2035 without the scheme.

3.2.4 Revised operational assessment tables to those provided in the Transport Assessment (document reference 7.2, section 7) are provided in Appendix A.

Table 3.1: Summary of operational assessment, 2020 without scheme

Junction

AM Peak PM Peak

CHARM2 CHARM3A CHARM2 CHARM3A

Max RFC/

DoS

Ave.

Delay

Max RFC/

DoS

Ave.

Delay

Max RFC/

DoS

Ave. Delay

Max RFC/

DoS

Ave. Delay

(%) (secs per veh)

(%) (secs per veh)

(%) (secs per veh)

(%) (secs per veh)

Swavesey Services roundabout

47% 3.0 29% 3.0 76% 3.0 43% 3.0

Bar Hill South roundabout 85% 6.6 81% 6.0 88% 9.0 95% 6.0

Histon junction 86% 69.0 83% 62.8 106% 127.6 108% 184.5

Milton junction 124% 307.2 186% 463.6 113% 131.9 129% 190.2

Hinchingbrooke/

Views Common junction 50% 4.4 39% 3.8 49% 4.5 40% 3.8

Brampton Road/Underpass junction

56% 4.4 41% 2.0 91% 7.8 71% 3.5

Brampton Road/

Hinchingbrooke Rd junction

44% 1.8 37% 1.7 77% 3.8 52% 2.1

Brampton Road/

Edison Bell Way junction 153% 239.7 68% 26.7 152% 453.8 78% 35.6

Ermine Street/Edison Bell Way junction

70% 25.7 54% 18.8 66% 25.4 58% 18.3

North West Cambridge junction

40% 11.3 36% 11.0 51% 12.5 58% 13.6


Table 3.2: Summary of operational assessment, 2035 without scheme

Junction

AM Peak PM Peak


Max RFC/

DoS

Ave.

Delay

Max RFC/

DoS

Ave.

Delay

Max RFC/

DoS

Ave. Delay

Max RFC/

DoS

Ave. Delay

(%) (secs per veh)

(%) (secs per veh)

(%) (secs per veh)

(%) (secs per veh)


30% 3.0 31% 3.0 38% 3.0 35% 3.0

Bar Hill South roundabout 92% 9.0 101% 14.4 101% 18.6 106% 14.4

Histon junction 92% 93.1 132% 243.8 129% 256.2 136% 321.1

Milton junction 145% 350.6 210% 494.2 84% 59.0 139% 312.6

Hinchingbrooke/

Views Common junction 50% 4.7 53% 5.1 48% 3.2 47% 3.2


56% 2.1 47% 2.0 76% 3.9 76% 4.1

Brampton Road/

Hinchingbrooke Rd junction

42% 1.8 41% 1.7 90% 7.3 74% 7.3

Brampton Road/

Edison Bell Way junction 125% 195.6 76% 31.9 183% 535.0 90% 535.0


70% 25.8 62% 21.1 66% 25.6 66% 24.4

North West Cambridge junction

55% 13.5 56% 13.7 61% 16.2 61% 16.3

3.2.5 From Table 3.1 and Table 3.2 it can be seen that, for the majority of junctions,

the results of the operational assessments based on CHARM3a traffic forecasts are similar to those reported in the Transport Assessment based on CHARM2 forecasts.

3.2.6 The main changes are around the Histon and Milton junctions, where there is deterioration in the forecast performance. The changes at Histon are due to the updates made to the model to reflect better the expected location of the access to the Darwin Green Phase 2 development. This results in more traffic routeing into Cambridge on the B1049, which results in greater levels of congestion on the Histon junction.

3.2.7 The changes at Milton are the result of an increase in forecast traffic flows

due to a change in the routeing of traffic travelling between the A428 to the west and the A10 to the north. In CHARM2 some of this traffic was forecast to use local roads through Dry Drayton and Oakington to avoid congestion on the Cambridge Northern Bypass. However, in CHARM3a this traffic is


forecast to remain on the A14, joining the A10 at Milton. This is primarily due to the changes made to the assumptions regarding External to External growth between the models which have resulted in a reduction in the volume of long distance traffic on the strategic routes, thereby freeing up capacity for more local traffic movements.

3.2.8 The southern roundabout at Bar Hill is forecast to operate with a slightly

higher RFC in both peak hours in 2035, with the junction forecast to be operating at capacity in the PM peak hour. This change is due to an increase in the volume of traffic from Northstowe joining the A14 at Bar Hill in CHARM3a compared with CHARM2. In CHARM2, more of this traffic was forecast to use the Local Access Road, joining the A14 at Swavesey.

3.2.9 The Brampton Road / Edison Bell Way junction in Huntingdon is forecast to

operate better in the CHARM3a assessment than it does in the CHARM2 assessment. This is due to the recent changes that have been made to the traffic signals at this junction, most notably increasing the cycle time from 90 to 120 seconds. These changes have been propagated through to the ‘Do-Minimum’ scenario in the CHARM3a assessment and result in significantly improved performance in both AM and PM peak hours.

3.2.10 Updated operational assessments have also been carried out for the ‘Do-

Something’, that is, ‘with scheme’, scenario. Table 3.3 and Table 3.4 summarise the average RFC / DoS on the worst performing arm and the average delay per vehicle for each junction in 2020 and 2035 with the scheme.

3.2.11 Revised operational assessment tables to those provided in the Transport Assessment (document reference 7.2, section 7) are provided in Appendix A.

Table 3.3: Summary of operational assessment, 2020 with scheme

Junction

AM Peak PM Peak


Max RFC/

DoS

Ave.

Delay

Max RFC/

DoS

Ave.

Delay

Max RFC/

DoS

Ave. Delay

Max RFC/

DoS

Ave. Delay

(%) (secs per veh)

(%) (secs per veh)

(%) (secs per veh)

(%) (secs per veh)

Ellington (N) roundabout

52% 3.6 62% 4.2 62% 4.2 74% 5.4

Ellington (S) roundabout

37% 3 43% 3.6 41% 3.6 50% 3.6

Brampton Road/Buckden Road roundabout

39% 3 36% 3.0 29% 3 37% 3.0


A14/A1198 (N) roundabout

40% 3 37% 3.0 31% 3 29% 3.0

A14/A1198 (S) roundabout

53% 3 51% 3.0 46% 3 41% 2.4

Swavesey (N) roundabout

71% 4.2 66% 4.2 50% 3 49% 3.0

Swavesey (S) roundabout

47% 3 49% 3.0 76% 4.2 70% 3.6


21% 3 22% 3.0 22% 3 28% 3.0

Swavesey Anderson Road roundabout

42% 3.6 39% 3.6 36% 3.6 41% 3.6

Bar Hill roundabout 31% 1.8 30% 1.8 53% 2.4 56% 2.4

Bar Hill (S) roundabout

45% 3.6 41% 3.0 71% 4.2 70% 4.2

Bar Hill/Local Access Road Junction

57% 19.7 61% 20.0 50% 17.8 51% 18.3

Dry Drayton (N) roundabout

42% 3 39% 3.0 34% 3 30% 3.0

Dry Drayton (S) roundabout

36% 3.6 36% 3.6 29% 3 28% 3.0

Girton (W) roundabout

29% 3 29% 3.0 38% 3 42% 3.0

Girton (E) roundabout 63% 4.8 65% 5.4 52% 4.8 59% 4.8

Histon junction 77% 55.7 82% 59.6 84% 64.2 111% 178.2

Milton junction 95% 84.0 101% 135.5 76% 50.5 84% 100.0

Views Common roundabout

37% 6 31% 2.4 50% 4.2 40% 2.4

Hinchingbrooke/Views Common junction

65% 26.4 59% 23.0 82% 34.5 61% 31.4


46% 1.0 46% 2.0 44% 1.4 46% 2.4

Brampton Rd/Hinchingbrooke Rd

66% 10.2 56% 14.4 57% 9.1 57% 14.6

Brampton Rd/Edison Bell Way junction

97% 72.6 85% 34.0 117% 156.6 99% 67.4


64% 7.3 66% 23.6 67% 8.0 69% 21.7

Mill Common Link/Pathfinder Link junction

60% 6.6 67% 7.2 58% 5.8 71% 8.3


Pathfinder Link/Ring Road junction

45% 6.6 74% 44.6 40% 5.4 62% 39.8

NW Cambridge junction

55% 11.2 55% 11.1 46% 12.1 54% 12.6

Table 3.4: Summary of operational assessment, 2035 with scheme

Junction

AM Peak PM Peak


Max RFC/

DoS

Ave.

Delay

Max RFC/

DoS

Ave.

Delay

Max RFC/

DoS

Ave. Delay

Max RFC/

DoS

Ave. Delay

(%) (secs per veh)

(%) (secs per veh)

(%) (secs per veh)

(%) (secs per veh)

Ellington (N) roundabout

59% 4.2 69% 4.8 54% 3.6 83% 7.2

Ellington (S) roundabout

51% 4.2 49% 4.2 39% 3.6 56% 4.2

Brampton Road/Buckden Road roundabout

40% 3 35% 3.0 27% 3 32% 3.0

A14/A1198 (N) roundabout

46% 3.6 45% 3.6 42% 3 38% 3.0

A14/A1198 (S) roundabout

63% 3.6 59% 3.6 62% 3.6 51% 3.0

Swavesey (N) roundabout

79% 4.8 79% 6.0 69% 3.6 70% 4.8

Swavesey (S) roundabout

57% 3.6 61% 3.6 73% 4.2 69% 3.6


25% 4.2 27% 3.0 28% 4.8 41% 3.6

Swavesey Anderson Road roundabout

55% 4.2 48% 4.2 57% 4.8 55% 4.8

Bar Hill roundabout 44% 2.4 46% 3.0 78% 4.2 85% 5.4

Bar Hill (S) roundabout

46% 3.6 45% 3.0 77% 4.8 77% 4.8


85% 29.7 90% 36.5 83% 27.2 84% 29.6

Dry Drayton (N) roundabout

54% 4.2 53% 4.2 51% 4.2 46% 3.6

Dry Drayton (S) roundabout

48% 4.2 49% 4.2 44% 4.2 47% 3.6

Girton (W) roundabout

48% 4.2 51% 3.6 52% 4.2 52% 4.2


Girton (E) roundabout 68% 4.2 75% 6.6 79% 4.2 85% 8.4

Histon junction 89% 63.6 132% 237.4 102% 68.9 131% 258.8

Milton junction 124% 207.3 111% 204.1 83% 47.2 85% 91.0

Views Common roundabout

44% 8.4 40% 2.4 60% 3.6 51% 3.0

Hinchingbrooke/Views Common junction

67% 13.1 75% 12.9 77% 18.0 72% 17.2


48% 1.0 47% 1.0 42% 1.1 45% 1.1

Brampton Rd/Hinchingbrooke Rd

67% 17.5 63% 18.0 58% 16.4 57% 16.5

Brampton Rd/Edison Bell Way junction

115% 127.6 98% 59.7 129% 165.4 102% 81.2


70% 9.3 71% 25.4 75% 11.5 71% 26.9

Mill Common Link/Pathfinder Link junction

64% 9.5 73% 8.8 57% 8.2 72% 9.1

Pathfinder Link/Ring Road junction

48% 23.1 87% 58.8 46% 28.1 71% 43.2

NW Cambridge junction

62% 14.1 65% 14.4 71% 18.5 77% 16.9

3.2.12 The conclusions of the operational assessments based on the CHARM3a

traffic forecasts are similar to those reported in the Transport Assessment (document reference 7.2) based on the CHARM2 forecasts. Most of the junctions are forecast to operate well within capacity (RFC / DoS of less than 85%).

3.2.13 As in the ‘Do-Minimum’ scenario, the main differences are at the Histon and Milton junctions. The changes are of a similar magnitude to those forecast in the ‘Do-Minimum’ scenario and have the same root causes. However, as before the performance of both junctions in the ‘Do-Something’ scenario is forecast to be the same as or better than that in the ‘Do-Minimum’ scenario (refer to Table 3.2), indicating that ‘nil-detriment’ is being achieved.

3.2.14 The performance of the Brampton Road / Edison Bell Way junction is also forecast to be better in the CHARM3a assessment than in the CHARM2 assessment. This improvement arises from a combination of a slight reduction in the volume of traffic using this junction and further optimisation of the traffic signal timings. Unlike the ‘traffic-optimised’ scenario reported in the Transport Assessment (document reference 7.2) which was forecast to achieve ‘nil-detriment’ in both peak hours, the assessment of the ‘Do-Something’ scenario based on the CHARM3a forecasts indicates that the


junction would be operating slightly better in the AM peak hour but slightly worse in the PM peak hour. The deterioration in performance in the PM peak hour is primarily due to the changes that are proposed at this junction for non-motorised users (NMUs) in the ‘Do-Something’ scenario. Specifically, the proposed junction layout would replace the existing two-stage crossing on Brampton Road (W) with a single stage crossing and would provide a new pedestrian crossing on the eastern side of the junction, both of which would improve north-south connectivity for NMUs.

3.2.15 Provision for NMUs is particularly important at this junction, with high flows, proximity to Huntingdon railway station and a National Cycle Route along Brampton Road. There are also a significant number of physical constraints which limit the geometry of this junction, number of lanes and capacity that can be provided, including: the existing Brampton Road bridge over the East Coast Mainline railway, Huntingdon railway station car park, and access to Mill Common.

3.2.16 The maximum DoS at the Pathfinder Link / Ring Road junction is forecast to be higher in the CHARM3a assessment than in the CHARM2 assessment in both peak hours. This change is due to an increase in the volume of traffic from the villages to the north of Huntingdon that is forecast to join the detrunked A14 in Huntingdon between the two versions of the model, and thereby routes through this junction.

3.3 Modifications required to accommodate CHARM3a 3.3.1 The results in Table 3.4 and Appendix B indicate that for the following

junctions, in the 2035 ‘Do-Something’ scenario with CHARM3a, the predicted performance is close to or over capacity:

• Bar Hill/Local Access Road junction;

• Histon junction; and

• Brampton Road/Edison Bell Way junction.

Bar Hill / Local Access Road

3.3.2 The assessments undertaken for the Bar Hill / Local Access Road junction indicate that the junction is forecast to operate close to capacity in both AM and PM peak hours.

3.3.3 To resolve potential queuing issues on the Hattons Road (N) entry introduced by CHARM3a modifications to the junction layout would be required as outlined in Figure 3.1.

3.3.4 These changes would reduce the degree of saturation from 90% to 77% maximum in the AM peak and 80% to 77% in the PM peak. A revised operational assessment table is contained in Appendix B.

3.3.5 Design to accommodate these changes has been undertaken, as well as an


environmental assessment, which confirms that this change would not require a change to the DCO and could be accommodated within the limits of deviation defined in the DCO.

Figure 3.1: Proposed modifications to Bar Hill Local Access Road junction

Histon Junction 3.3.6 The assessments undertaken for the Histon junction indicate that, as per the

‘Do-Minimum’ scenario, the junction is forecast to operate above capacity in both peak hours. The performance in the ‘Do-Something’ scenario is the same or marginally better than the ‘Do-Minimum’ scenario, so ‘nil-detriment’ is achieved. As detailed in Appendix B, the Cambridge Road arm is over capacity, as was the case with CHARM 2. Performance of the B1049 arm, as detailed in Appendix B, is now such that the saturation on this arm has increased to 89%.

3.3.7 To improve performance, a slightly modified junction layout has been considered as shown in Figure 3.2.

3.3.8 In the modified layout a short length of northern circulatory carriageway between the Cambridge Road exit and entries is locally widened to three lanes, which provides more storage space and with re-optimisation of the


traffic signal timings improves the performance of the junction. 3.3.9 The revised layout significantly improves the performance of the B1049

approach, reducing saturation in the AM peak from 89% to 67%. Broadly, the performance of the rest of the junction is similar, with ‘nil-detriment’ being maintained. The revised operational assessment table is contained in Appendix B.

3.3.10 Design to accommodate these changes has been undertaken, as well as an environmental assessment, which confirms that this change would not require a change to the DCO and could be accommodated within the limits of deviation defined in the DCO.

Figure 3.2: Proposed modification to Histon Junction

Brampton Road / Edison Bell Way junction 3.3.11 The CHARM3a ‘Do-Something’ results for this junction show that its operation

is improved compared to the CHARM2 analysis, with a degree of saturation of 98% compared with 115% in the AM peak and 102% compared with 129% in the PM peak.


3.3.12 If the projected traffic flows materialise at Brampton Road / Edison Bell way junction, this degree of saturation would manifest itself in the design year (2035) as congestion for a period during the AM and PM peak hours.

3.3.13 There is, however, a greater improvement in the ‘Do-Minimum’ results. In addition to the traffic changes resulting from CHARM3a, this is due to the signal timings being updated to match the 120 second cycle time that is currently being used. ‘Nil-detriment’ is therefore not achieved.

3.3.14 The conflicting right turning movements from Brampton Road into Mill Common Link and from Edison Bell Way into Brampton Road are the critical movements governing the operation of the signals in the ‘Do-Something’ scenario. The layout of this junction cannot be improved to provide increased capacity due to physical constraints which limit junction geometry. These constraints include the existing Brampton Road bridge over the East Coast Mainline Railway, Huntingdon railway station car park and access to Mill Common.

3.3.15 Noting that the performance of the proposed junction has improved since CHARM2 and that revisions to the junction are not practicable, it is considered that the performance of this junction is the best that can reasonably be provided, even if ‘nil-detriment’ is not achieved.

3.3.16 Furthermore, it is recognised that measures to increase junction capacity at this location may prove counter-productive and that any improvements would likely attract additional traffic, leading to reduced performance.

3.4 Sensitivity testing of proposed development at Northstowe 3.4.1 The operational assessments undertaken for the ‘Do-Something’ scenario as

described in sections 3.2 and 3.3 are based on 2,315 homes at Northstowe in 2020, increasing to 5,031 homes by 2035. For reporting purposes the ‘Do-Something’ scenario is referred to as ‘DS+’.

3.4.2 The Northstowe Area Action Plan ultimately includes plans for up to 10,000

homes. Planning approval has not yet been granted for these additional homes and therefore they are not included as part of the ‘core’ scenario. Nonetheless, Highways England has committed to safeguard land and provide earthworks and structures at Bar Hill that are capable of accommodating the full build out of Northstowe, providing a scheme such that only relatively modest alterations would be required to be implemented by the developer to accommodate the full build out and hence limit disruption to the travelling public.

3.4.3 Accordingly, other junctions in the vicinity of the Northstowe development have also been assessed to determine whether proposed junction designs are capable of accommodating the additional traffic generated by the development.


3.4.4 In order to ensure that the junction designs are robust, a series of operational assessments have been undertaken for the 2035 ‘high development’ scenario (refer to the Transport Assessment document reference 7.2, Table 3.7), which includes full build out of Northstowe to 10,000 homes. For reporting purposes the ‘Do-Something’ scenario is referred to as ‘DS++’.

3.4.5 The following junctions in the vicinity of the development have been assessed against a DS++ scenario:

• Swavesey North roundabout;

• Swavesey South roundabout;

• Swavesey Services roundabout;

• Swavesey Anderson Road roundabout;

• Lolworth junction;

• Bar Hill Main roundabout;

• Bar Hill South roundabout;

• Bar Hill / Local Access Road junction;

• Dry Drayton North roundabout;

• Dry Drayton South roundabout;

• Girton Interchange West roundabout; and

• Girton Interchange East roundabout.

3.4.6 Table 3.5 summarises the results of the DS++ assessments and includes a comparison against DS+ assessments.

Table 3.5 2035 DS++ junction capacity assessments, maximum RFC / DoS (%)

Junction

AM Peak PM Peak

DS+ DS++ %

Change DS+ DS++

% Change

Swavesey (North) 79% 88% +9% 70% 96% +26%

Swavesey (South) 61% 73% +12% 69% 76% +7%

Swavesey Services 27% 29% +2% 41% 59% +18%

Swavesey Anderson Road

48% 39% -9% 55% 58% +3%

Lolworth 3% 1% -2% 2% 1% -1%

Bar Hill (Main) 46% 64% +18% 85% 78% -7%

Bar Hill (South) 45% 47% +2% 77% 82% +5%

Bar Hill/Local Access Road(1)

90% 78% -12% 84% 74% -10%

Dry Drayton (North) 53% 66% +13% 46% 68% +22%


Dry Drayton (South) 49% 68% +19% 47% 61% +14%

Girton (W) 51% 55% +4% 52% 58% +6%

Girton (E) 75% 74% -1% 85% 89% +4%

3.4.7 For the Bar Hill junction, the results in the DS++ scenario are based on the

local access road junction being modified as per Figure 3.1 – this change being required to accommodate CHARM 3a figures. All other junction designs are as per those submitted as part of the DCO application.

3.4.8 The results show that junctions operate within capacity with the full build of Northstowe, albeit with increased saturation.

3.4.9 At Bar Hill junction, to provide an additional robustness to cater for future traffic flows, the design as submitted as part of the DCO application provides passive provision in the earthworks and bridges for widening the circulatory carriageway of the roundabout to three lanes.

3.5 Link capacity assessments 3.5.1 This section of the Traffic Modelling Update Report assesses the required

lane provision for the scheme in response to CHARM3a traffic forecasts. The assessment has identified the number of lanes required on each section of the A1 and A14 within the scheme limits based on forecast traffic flows and four assessment methods based on Department for Transport Design Manual for Roads and Bridges (DMRB) guidance.

3.5.2 The method of assessment is the same as that used in the Transport

Assessment (document reference 7.2, section 7.10.2) and is based on the following four assessment methods:

• Method A: Carriageway Standard;

• Method B: Congestion Reference Flow (CRF);

• Method C: Lane Capacity; and

• Method D: Number of lanes required for weaving.

3.5.3 The above assessments have been carried out for both the opening year (2020) and a future forecast year (2035). The results of the assessments have been summarised using a RAG rating system, which is defined as follows:

• Green: Sufficient provision until design year (2035);

• Amber: Sufficient provision until design year, but may fall below the desired level of service before the design year; and

• Red: Falls below the provision required by current standards before the design year.

3.5.4 Table 3.6 and Table 3.7 summarise the results of the assessments for the


opening year (2020) and future forecast year (2035) respectively, and provide a comparison with the assessment results presented in the Transport Assessment (document reference 7.2) as submitted as part of the DCO application.

Table 3.6: Summary of A1 and A14 link capacity assessments, 2020 (‘with scheme’ scenario)

Section Proposed standard

Method A C’way

Standard, DMRB

standard

Method B Congestion Reference Flow, ratio

Method C Lane

Capacity, ratio

Method D Weaving Flows,

number of lanes

12

(number of lanes

13)

CH

AR

M 2

CH

AR

M 3

a

CH

AR

M 2

CH

AR

M 3

a

CH

AR

M 2

CH

AR

M 3

a

CH

AR

M 2

CH

AR

M 3

a

A1 Alconbury To Brampton Hut

D3AP D3M D3M 0.51 0.51 0.49 0.49 N/A N/A

A1 Brampton Hut to

Brampton Interchange

D3AP D4M D4M 0.59 0.58 0.55 0.57 2.7

(2.3) 2.8

(2.7)

A14 Ellington to


D2AP D3AP D3AP 0.44 0.41 0.41 0.40 N/A N/A

A14 Brampton Interchange to Ermine Street

D3AP D4M D4M 0.58 0.55 0.56 0.51 N/A N/A

A14 Ermine Street to Swavesey

D3AP D3M D3M 0.50 0.48 0.47 0.45 N/A N/A

A14 Swavesey to Bar Hill

D3AP D4M D4M 0.72 0.68 0.69 0.65 2.4

(2.1) 2.4

(2.1)

A14 Bar Hill to Girton Interchange

D4AP D4M+ D4M+ 0.64 0.62 0.62 0.59 N/A N/A

A14 Girton Interchange to Histon

D3AP D4M D4M 0.81 0.79 0.76 0.74 3.2

(2.8) 3.3

(2.8)

A14 Histon Junction to Milton

D3AP D4M D4M 0.77 0.78 0.72 0.73 3.0

(2.6) 3.3

(2.7)

12 Number of lanes using 1600vpd capacity. 13

Number of lanes using increased lane capacity calculated by Method C.


Table 3.7: Summary of A1 and A14 link capacity assessments, 2035 (‘with scheme’ scenario)

Section Proposed standard

Method A C’way

Standard, DMRB

standard

Method B Congestion Reference Flow, ratio

Method C Lane

Capacity, ratio

Method D Weaving Flows,

number of lanes

14

(number of lanes)

15

CH

AR

M 2

CH

AR

M 3

a

CH

AR

M 2

CH

AR

M 3

a

CH

AR

M 2

CH

AR

M 3

a

CH

AR

M 2

CH

AR

M 3

a

A1 Alconbury To Brampton Hut

D3AP N/A N/A 0.67 0.65 0.65 0.57 N/A N/A

A1 Brampton Hut to


D3AP N/A N/A 0.71 0.66 0.69 0.64 3.1

(2.8) 3.3

(2.9)

A14 Ellington to


D2AP N/A N/A 0.62 0.49 0.58 0.47 N/A N/A

A14 Brampton Interchange to Ermine Street

D3AP N/A N/A 0.81 0.68 0.72 0.61 N/A N/A

A14 Ermine Street to Swavesey

D3AP N/A N/A 0.74 0.57 0.63 0.53 N/A N/A


D3AP N/A N/A 0.88 0.76 0.80 0.73 2.9

(2.5) 2.7

(2.4)

A14 Bar Hill to Girton Interchange

D4AP N/A N/A 0.74 0.72 0.71 0.69 N/A N/A

A14 Girton Interchange to Histon

D3AP N/A N/A 0.94 0.89 0.88 0.83 3.6

(3.0) 3.8

(3.2)

A14 Histon Junction to Milton

D3AP N/A N/A 0.95 0.84 0.89 0.78 3.5

(3.0) 3.5

(2.9)

3.5.5 From Table 3.6 and Table 3.7 it can be seen that predicted traffic flows have

generally reduced, which would indicate an improved situation against that presented in the DCO application.

14

Number of lanes using 1600vpd capacity. 15

Number of lanes using increased lane capacity calculated by Method C.


3.5.6 For Method B (Congestion Reference Flow) and Method C (Lane Capacity), once the RFC is 0.85 or above there is a risk of degradation in flow conditions and risk of congestion. Of these two methods, Method C is considered to be the more accurate. With CHARM3a traffic flows, this ratio is reduced in all cases and is less than 0.85.

3.5.7 For Method D calculations CHARM3a traffic flows indicate slightly increased weaving flows on two mainline links (the A1 between Brampton Hut and Brampton Interchange and the A14 between Girton Interchange and Histon junction). However, it should be noted that these minor increases are not significant enough to require additional mainline lanes.

3.5.8 There are two locations where both CHARM2 and CHARM3a forecasts indicate insufficient capacity to accommodate calculated weaving flows; the A14 between Girton Interchange and Histon Junction, and the A14 between Histon Junction and Milton Junction. It should be noted that when calculated capacities using Method C are used in the weaving calculation, there is sufficient capacity on all links to accommodate weaving flows.

3.6 Merge and diverge assessments

3.6.1 This section of the Traffic Modelling Update Report outlines ‘Do-Something’ assessments for all merge and diverge sections within the A14 scheme study area. The operational capacity of the A14 slip roads have been assessed by reference to the merge/diverge criteria set out in TD 22/06 Layout of Grade Separated Junctions of the DMRB (Volume 6 Section 2 Part 1). This design guidance sets out the thresholds for different merge and diverge layouts and provides an assessment tool for comparing observed and predicted traffic flows against layout options.

3.6.2 Table 3.8 summarises the different types of merge and diverge as defined in TD 22/06 Layout of Grade Separated Junctions.

Table 3.8: Summary of merge and diverge types

Type Merge Type Diverge Type

A Taper Taper

B Parallel Merge Ghost Island or Parallel

C Ghost Island Lane Drop

D 2 Lane Urban Merge Ghost Island or Lane Drop

E Lain Gain 2 Lane Drop

F Lane Gain with Ghost Island N/A

G 2 Lane Gain with Ghost Island N/A

H Alternative Ghost Island Merge N/A

3.6.3 Table 3.9 identifies the proposed and required junction type for each identified

merge or diverge section in accordance with TD 22/06 for 2035.


3.6.4 Where the proposed merge or diverge arrangement requires a departure16,

and where the proposed layout type varies from the required type, the justification for this has been noted. It should be noted that, as stipulated in design standards, departures could result from over-provision (for example, as a result of providing more lanes than the standard indicates) as well as under-provision (for example, where a compact layout is proposed due to physical constraints).

Table 3.9: Merge and diverge assessments, 2035 ‘with scheme’ scenario

Merge/ Diverge description

Layout type as

per standard

with CHARM 2

Proposed

Layout type

as DCO application

Layout type as

per standard

with CHARM

3a

Proposed

Layout type Reason for departure

Alconbury Junction

A1 SB merge A A A A No departure required

A1 NB diverge C A A A No departure required

Brampton Hut Junction

A1 NB merge A A A A No departure required

A1 SB merge E B E B Type B merge proposed to suit agreed dual three lane layout of A1 upstream

A1 NB diverge A A C A Type A diverge proposed to allow the agreed three lane layout of A1 upstream

A1 SB diverge A A A A No departure required

Ellington Junction

A14 EB diverge

A A A A No departure required

A14 WB merge

B B A or D/E B

Over provision due to previous traffic requirements and for safety – as the merge is on inside of a relatively tight bend

16

A departure in standards relating to the DMRB. A number of DMRB documents contain within them provision for ‘Relaxations’ where experience has shown that certain requirements may be varied within defined limits in particular situations. However, any further variation beyond these limits requires Highways England to approve a ‘Departure’.



A14 WB merge with A1 NB

F F F F No departure required

A1 SB diverge to A14 EB

D D D D No departure required

A14 WB diverge to A1 NB


A1 SB merge with A14 EB


A1198 Junction

A14 WB merge

B B B B No departure required

A14 EB diverge


Swavesey Junction

A14 WB merge

A A A or D A No departure required

A14 EB merge F H E or F F

It is proposed to continue 3 lanes on the mainline through the junction. This is incompatible with a lane gain layout, therefore a Type H merge is proposed

A14 WB diverge

B B C or D B

It is proposed to continue 3 lanes on the mainline through the junction. This is incompatible with a lane drop layout, therefore a Type B diverge is proposed

A14 EB diverge

A A A or C A No departure required

Cambridge services EB diverge


Bar Hill Junction

A14 WB merge

A A A or D A No departure required

A14 EB merge F F B, E or F F No departure required

A14 WB diverge

D D A or D D No departure required

A14 EB diverge

A A A A

No departure required


Girton Interchange

A14 EB merging with A428 EB


M11 loop merge to A428 EB

E E C E

The proposed layout complies better with the standards, although a departure is still required.

A14 WB merge to M11 NB

G G G G No departure required

LAR merge to A14 WB

A or D B A or D B

No departure required - Type B layout is required by standards as radius of mainline is lower than desirable min

A14 WB diverge to A428 WB


A14 EB diverge to M11 SB

D E D D

No departure now proposed (Layout can be revised within DCO limits, to provide a Type D layout, avoiding a departure from standard.)

A14 WB diverge to M11 SB

D B D B Three lanes are proposed on mainline upstream hence layout is not a lane drop

M11 SB diverge to A1307

C A C C

No departure now proposed (Layout can be revised within DCO limits, to provide a Type C layout, avoiding a departure from standard)

Histon Junction

A14 WB merge

E B E B

Traffic figures require marginally more than one lane on the slip road. A single lane parallel merge is proposed to avoid impacting on Woodhouse Farm

A14 EB merge B B B B No departure required


A14 WB diverge

C B C A

Type A - needed for solution to remove impact on Orchard Park development therefore departure required

A14 EB diverge

B B B B No departure required

Milton Junction

A14 WB merge

G with 4 lanes on downstre

am mainline

F F F No departure required

A14 EB diverge


3.6.5 The CHARM3a flows on their own do not require any changes to the merge or diverge layouts as presented in the DCO application submitted in December 2014. There are a small number of changes for other reasons, that would be required to be incorporated in the design, and these are discussed below.

3.6.6 For the A14 eastbound heading towards Girton Interchange, the Transport Assessment (Document reference 7.2, Table 7.73) identified that, with CHARM2 flows, the following lane layout would be required with diverge types to suit:

• Four lanes on the A14 eastbound from Bar Hill Junction to where the A14 diverges;

• Three lanes from this point to where the A1307 diverges; and

• Two lanes on the M11 south of the above. 3.6.7 However, as also reported in the Transport Assessment (document reference

7.2, Table 7.73), the following lane layout, with diverge types to suit, was proposed (which would require departures from standard):

• Four lanes on the A14 eastbound from Bar Hill to where the A14 diverges;

• Two lanes from this point to where the A1307 diverges; and

• Two lanes on the M11 south of the above.

3.6.8 In light of CHARM3a flows the above proposals have been re-appraised and it is now proposed to provide the layout as per 3.6.6 above, which is in accordance with standards and provides increased capacity. The extent of change required at this is presented in Figure 3.3. This amendment can be accommodated within the limits of deviation defined in the DCO and therefore no change to the DCO application is required.

3.6.9 At the A14 eastbound heading towards Girton Interchange, amendments to the scheme design against that submitted as part of the DCO application can be accommodated within the limits of deviation defined in the DCO and


therefore no change to the DCO application is required. The extent of change required at this location to accommodate CHARM3a flows is presented in Figure 3.3.

Figure 3.3: Revised A14 eastbound diverge to M11 and M11 southbound to A1307 diverge arrangement at Girton

3.6.10 At the A14 Histon Westbound diverge a Type B auxiliary lane diverge is

required in response to CHARM3a flows. The Type B layout has an auxiliary lane (effectively making the A14 four lanes at the above location) which would lead to works (including sign gantries) encroaching into the adjacent Orchard Park development.

3.6.11 Consequently, a more compact Type A layout is therefore proposed, to avoid impacting on the development. As the flows are only marginally over the threshold for a Type A taper diverge, a Type A arrangement would operate within capacity for the great majority of its design life. This would require a departure from standards which is considered to be a suitable compromise given the constraints. The extent of change at this location is presented in Figure 3.4. As the change would be a reduction in the scope of works it could be accommodated within the limits of deviation defined in the DCO and therefore no change to the DCO application would be required.


Figure 3.4: Modifications required to minimise impact on adjacent development at Histon westbound diverge

3.7 Conclusions Operational assessment

3.7.1 The CHARM3a operational assessment for A14 junctions is generally

satisfactory and any changes required can be accommodated within the DCO. The exception is Brampton Road / Edison Bell Way junction in Huntingdon where, whilst the results predicted are significantly better than CHARM2, improvement in the ‘Do-Minimum’ scenario means ‘nil detriment’ cannot be achieved.

3.7.2 If the projected traffic flows materialise at Brampton Road / Edison Bell way

junction, this degree of saturation would manifest itself in the design year (2035) as congestion for a period during the AM and PM peak hours.

Northstowe high development sensitivity test

3.7.3 Sensitivity tests indicate that junctions with layouts which suit CHARM3a

would operate within capacity, albeit at higher levels of saturation, with no further modifications necessary. Link capacity assessment

3.7.4 No changes are required to either the A14 or A1 lane layouts or merges and

diverges resulting from the use of the CHARM3a traffic figures.

Merge/Diverge assessment 3.7.5 No changes to either the A14 or the A1 merge or diverge layouts result from

the use of the CHARM3a figures with the exception of the A14 eastbound diverge at Girton Interchange and the A14 westbound diverge at Histon, modifications to which can be accommodated within the limits of deviation defined in the DCO.


4 Environmental assessment

4.1 Introduction Purpose and scope

4.1.1 As outlined in section 2.1, the transport model which underpins the

Development Consent Order (DCO) application for the scheme is version 2 of the Cambridge to Huntingdon A14 Road Model, which is also referred to as CHARM2. Consequently, the Environmental Statement (ES) submitted as part of the DCO application (document reference 6.1) is based on CHARM2 data.

4.1.2 This section summarises findings of detailed air quality and noise modelling carried out using CHARM3a data. It also summarises the findings from a screening exercise for other environmental topics.

General approach

4.1.3 Detailed air quality and noise assessments were undertaken using the same

methodology as presented in the ES (which was based on CHARM2), but using CHARM3a data. These were undertaken to identify if there were any likely significant changes to the conclusions presented in the ES.

4.1.4 A high level screening exercise was undertaken to confirm whether the new traffic data would result in any significant changes to the overall findings of all other relevant environmental factors as presented in the ES.

4.2 Air quality 4.2.1 An air quality assessment was undertaken using the same methodology as

presented in the ES, but using CHARM3a data, to check if there were any significant changes to ES conclusions.

4.2.2 This air quality assessment provides information where it was considered that the use of CHARM3a data in the assessment could affect the ES results. The final assessment results are provided along with further detail on the results in key assessment areas such as Air Quality Management Areas (AQMAs) and Brampton. Methodology

4.2.3 The method of assessment and guidance used is the same as used within the

ES.

4.2.4 One new guidance document was released in the period following the submission of the DCO application. This was Interim Advice Note (IAN) 185/15 Updated traffic, air quality and noise advice on the assessment of link


speeds and generation of vehicle data into ‘speed-bands’ for users of DMRB Volume 11, Section 3, Part 1 Air quality and Volume 11, Section 3, Part 7 Noise (Highways Agency, January 2015). For consistency, this new IAN has not been used in the CHARM3a assessment to enable a ‘like for like’ comparison with the CHARM2 data assessed in the ES.

4.2.5 It should be noted that IAN 185/15 and its application in air quality assessment is the subject of the Q1.1.2 of the Examining Authority’s first written questions.

Study area

4.2.6 The study area of the CHARM3a assessment was defined using the same

criteria as set out in the ES (document reference 6.1, section 8.2.4). The change in traffic data resulted in a smaller affected road network (ARN) for the local air quality assessment. The ARN was defined in the same way as described in section 8.2.5 of the ES. Despite the area being smaller, the CHARM3a data resulted in five new roads being added to the ARN which were not assessed within the ES. The new road locations can be seen in Figure 4.1 where the CHARM2 and CHARM3a ARN areas do not overlap. The results on these roads showed no significant impacts would occur and modelled concentrations at all receptors were below the annual mean NO2 limit value (40µg/m3). One receptor on the new links experiences a ‘small’ increase in NO2 (less than 2µg/m3). All other new receptors either experience an improvement in air quality or a negligible increase (less than 0.4µg/m3).

Figure 4.1: Comparison of CHARM3a and CHARM2 affected road networks


4.2.7 The regional assessment area was defined in the same way as described in

section 8.2.7 of the ES. The CHARM3a regional assessment area is larger than the CHARM2 assessment area. However the overall conclusions of the regional assessment do not change. The WebTAG valuation assessment now shows the total CO2 cost of the scheme to be £119 million, which is a reduction of around £88 million compared with the CHARM2 figures. Model verification

4.2.8 The CHARM3a data were provided for all scenarios considered in the ES (section 8.2.23). As new baseline traffic information was provided a revised model verification exercise was undertaken. The verification exercise was undertaken using the same method as described in the ES (section 8.2.51).

4.2.9 Local air quality management technical guidance (LAQM TG(09)) (Defra, February 2009) suggests that if modelled annual mean NO2 concentrations are within ±25% and preferably within ±10% of the monitored concentration and there is no systematic under or over prediction, then model adjustment is not considered necessary to further improve modelled results. IAN 174/13 (Highways Agency, 2013) notes the desirability of achieving ±10% verification where concentrations are close to or above the air quality threshold.

4.2.10 Using the same approach as the ES two verification factors were used, one for the majority of the assessment area and another for the centre of Huntingdon. The verification factor for the main assessment area for CHARM3a was 1.07. This compared to 1.08 for the CHARM2 assessment. The verification factor for the Huntingdon town centre for CHARM3a was 2.47 compared to 2.53 for the CHARM2 assessment (see Table 4.1).

4.2.11 The small changes in verification factors between the two assessments results in no significant changes in conclusions compared to the ES.

Table 4.1: Summary of verification factors

CHARM2 verification CHARM3a verification

Huntingdon town centre

verification

Rest of ARN area

verification

Huntingdon town centre

verification

Rest of ARN area

verification

Verification factor

2.53 1.08 2.47 1.07

Within +10% 2 7 2 2

Within -10% 0 6 0 8

Within ±10% 2 13 2 10

Within +10 to 25%

1 2 1 6

Within -10 to 25%

1 4 1 4


Within ±10 to 25%

2 6 2 10

Over +25% 0 1 0 0

Under -25% 0 0 0 0

Greater ±25% 0 1 0 0

Within ±25% 4 19 4 20

Total 4 20 4 20

4.3 Air quality results

CHARM3a modelled flows 4.3.1 No significant impacts are predicted at any sensitive receptor locations, either

human or ecological using either the CHARM2 or the CHARM3a datasets.

4.3.2 These results are based on the sensitivity analysis of future year NOX

reductions as recommended in the IAN 170/12 v3 (Highways Agency, 2013) using annual projection factors between 2008 and 2030. These factors are considered to be a conservative estimate of future emission trends.

4.3.3 The results of the CHARM3a assessment follow the ES results in terms of identifying that the scheme will have a positive effect on urban areas in Fenstanton and Huntingdon.

4.3.4 The results at predicted receptors are shown in Appendix D. The figures in Appendix D show both the CHARM2 modelled results and the CHARM3a predicted NO2 and PM10 concentrations in 2020. Figures show the change in concentration between the ‘Do-Minimum’ and ‘Do-Something’ modelled scenarios. No exceedances of the annual mean objectives for NO2 or PM10 are predicted at any receptor. AQMAs

4.3.5 The overall conclusion for air quality effects in AQMAs remains the same as presented in the ES. A summary of the results within the AQMAs, highlighting any differences between the results of CHARM3a against CHARM2, is shown in Table 4.2.


Table 4.2: AQMA summary results

Air Quality Management Area

Modelled Results

Huntingdon Concentrations of NO2, are generally predicted to improve across most of the AQMA.

There is some localised reduction in improvements but this will not affect compliance with the objective and limit values.

There are improvements in the section of AQMA which extends towards Godmanchester.

The CHARM3a results do not change any conclusions of the ES. In some locations the revised data results in an increase in the predicted concentrations of over 1µg/m

3. The greatest

change is at a location on the one way system in the town centre at the junction of St. Marys Street and Castle Moat Road where a 3µg/m

3 improvement was predicted in CHARM2

and a 1.8µg/m3 increase is predicted in CHARM3a.

The CHARM3a traffic data indicates a reduction in speeds as a result of the scheme at this location compared to CHARM2 traffic data. There are also smaller reductions in traffic as a result of the scheme using CHARM3a data compared with CHARM2 data.

Concentrations at this location remain below the objective and limit values.

The CHARM3a results predict a smaller improvement around the Huntingdon ring road compared with CHARM2, this is due to reduced speeds in the CHARM3a data compared with the CHARM2 data.

Brampton Concentrations in the Brampton AQMA are already below the air quality objectives.

The modelled results indicate that the scheme would benefit air quality in this location.

The CHARM3a results show an improvement compared to the CHARM2 results with greater benefits to air quality seen within this AQMA with the CHARM3a traffic data.

Hemingford – Fenstanton A14

With this section of the A14 becoming much less trafficked in 2020 as a result of the scheme, pollutant concentrations at this location have been predicted to improve in this AQMA.

The concentrations have currently been monitored below the objectives and with the scheme they are predicted to reduce further.

The CHARM3a data is predicted to improve NO2 annual mean concentrations in the AQMA. The predictions using CHARM2 and CHARM3a data agree to within 0.4µg/m

3 at all locations.


A14 corridor No exceedances of either the NO2 or PM10 objective are predicted in the opening year for the A14 corridor AQMA.

The CHARM3a results generally predict a smaller improvement compared with the CHARM2 results in the ES.

There are five locations within the AQMA where concentrations are predicted to increase by more than 1µg/m3 compared to the ES results. These five locations are all on the western side of the A14 at Hackers Farm and Catchall Farm cottages. These locations are the sites where the highest concentrations were predicted within the ES. However the predicted concentrations are still below the air quality objectives and limit values for annual mean NO2 (approximately 32µg/m3).

Compliance with the Air Quality Directive

4.3.6 The method of assessment using IAN 175/13 is the same as that used in the

ES. The compliance risk road network (CRRN) identified using CHARM2 data did not change using the CHARM3a data. No new Pollution Climate Mapping (PCM) links overlapped with the ARN.

4.3.7 The conclusions within the ES regarding the scheme’s compliance with the directive do not change as a result of CHARM3a data. The scheme would still be deemed low risk following the method within the IAN. None of the links were at risk of becoming non-compliant, the date for achieving compliance would not be affected and there would be no increase in the length of roads in exceedance in the zone WebTAG

4.3.8 The local and regional WebTAG do not provide any change in conclusions to

the WebTAG assessment using CHARM2 data. The overall number of receptors affected by the scheme has reduced as a result of the reduced ARN for the local air quality assessment. The majority of properties experience an improvement in NO2 and PM10 concentrations, which aligns with the original WebTAG assessment using CHARM2 data. The social and distributional impacts are also similar and a substantial beneficial effect remains when using the CHARM3a data. As discussed above, the total CO2 cost of the scheme is reduced using CHARM3a data compared to CHARM2 data. In addition to this, the present value associated with the change in NOx emissions as a result of the scheme is also reduced using CHARM3a data compared to CHARM2 data.

Conclusions

4.3.9 There are no significant changes predicted in AQMAs and in all modelled areas across the scheme compared to the ES results submitted as part of the DCO application in December 2014. The overall conclusions of the ES remain valid. Furthermore, there is no predicted risk of exceeding air quality limit values on PCM links. While there is a predicted increase in CO2 emissions as a result of the scheme compared with the ES results, the negative impact of


greenhouse gas is reduced as a result of CHARM3a data (refer to section 5 for further detail of monetised benefits).

4.4 Noise Introduction

4.4.1 An initial risk review was undertaken during March 2015 to evaluate whether CHARM3a data would have changed the noise assessment outcomes reported in the ES. This review identified that there was some risk of adverse change (noise increases) in the Alconbury area.

4.4.2 A full sensitivity test using the same methodology as presented in the ES has therefore since been undertaken to confirm if there are any significant changes to the conclusions of the noise assessment presented in the ES or the WebTAG assessment.

4.4.3 This section reports on the full sensitivity study. Method and guidance

4.4.4 The method of assessment and guidance used for the appraisal of CHARM3a impacts is the same as that used in the ES.

4.4.5 One new guidance document was released in the period following the submission of the ES. This was IAN 185/15 Updated traffic, air quality and noise advice on the assessment of link speeds and generation of vehicle data into ‘speed-bands’ for users of DMRB Volume 11, Section 3, Part 1 Air quality and Volume 11, Section 3, Part 7 Noise. For consistency, this new IAN has not been used in the CHARM3a sensitivity assessment to enable a ‘like for like’ comparison with the CHARM2 data assessed in the ES.

4.4.6 It should be noted that IAN 185/15 and its application in noise assessment is the subject of the Q1.10.4 of the Examining Authority’s first written questions.

Study area

4.4.7 The DMRB approach had been followed to define the spatial scope of the environmental impact assessment, that is, ‘600m around new or altered highways and section of existing roads within 1km of the new works that are predicted to be subject to a change in noise level of more than 1dB(A) as a result of the scheme on opening in 2020’.

4.4.8 This applies to connecting local roads such as the radial routes into Cambridge connecting to the Cambridge Northern Bypass.

4.4.9 The sensitivity tests using CHARM3a confirm that no additional roads would be subject to change of more than 1dB(A). Therefore the spatial scope used for the ES remains unchanged. The noise study area is shown in Figure 4.2.


Detailed results

4.4.10 The assessment of noise effects reported in the ES has been undertaken based on quantitative information at a large number of Assessment Locations as noted in Volume 6.3, Appendices 14.5 and 14.6, and as shown on Volume 6.2, Figure 14.1, Figure 14.3, Figure 14.5 and Figure 14.7 of the ES.

4.4.11 Each of the Assessment Locations is representative of a number of dwellings. In this way all residential receptors within the study area (as defined in section 14.2 of Chapter 14, Volume 6.1 of the ES and Figure 4.3 of this note) have been considered.

4.4.12 The number of residential dwellings represented by each Assessment Location is recorded in the assessment tables in Appendix 14.5 and Appendix 14.6 of Volume 6.3 of the ES (in the column titled “Number of Residential” for each Assessment Location).

4.4.13 A key component of the assessment of noise effects is the evaluation of noise change brought about by the scheme.

4.4.14 The ES assessment focuses on long term noise change (the worst case). This has been evaluated by comparing noise levels calculated for the ‘Do-Something’ scenario (with the proposed scheme) in 2035 with those calculated for the ‘Do-Minimum’ scenario (without the proposed scheme) in 2020 (scheme opening year).

4.4.15 Sheet 25 of Figure 14.7 in Volume 6.2 of the ES summarises the noise change impacts calculated at all Assessment Locations within the study area. These data from this ES Figure is reproduced here as Figure 4.3 and is based on CHARM2 data.

4.4.16 Figure 4.4 is the equivalent to Sheet 25 of Figure 14.7 in Volume 6.2 of the ES but is based on CHARM3a data rather than CHARM2 traffic data.

4.4.17 Comparing Figure 4.3 and Figure 4.4 shows that there is no significant difference between the noise impacts identified between CHARM2 and CHARM3a traffic data and as shown in Table 4.3 there would be no new adverse significant effects with the CHARM3a data.

4.4.18 Figure 4.4 highlights where there are two areas with slightly larger, but non-significant, differences in the noise level change calculated between CHARM2 and CHARM3a. Each of these differences is discussed in greater detail in Table 4.4.


Figure 4.2: Noise assessment study area

Figure 4.3: Noise change impact summary, CHARM 2


Figure 4.4: Noise change impact summary, CHARM3a

Notes:

1) For information on Detail #1 and Detail #2 refer to Table 4.4.


Table 4.3: Summary of significant community noise effects for CHARM2 and CHARM3a prediction models

Reporting Section Significant effects based on CHARM2 (ES)

Significant effects based CHARM3a

Section 1: A1 Alconbury to Brampton Hut

No significant effects No significant effects

Section 2: A1/A14 Brampton Hut to East Coast Main Line

Adverse significant effects (approx. 260 dwellings):

ON-C04(S): Dwellings in the vicinity of Stewart Close on the west edge of Brampton

ON-C05(S): Dwellings on the west edge of RAF Brampton

ON-N01(BA): Premier Inn, Brampton

Beneficial significant effects (approx. 140 dwellings):

ON-C02(BA): Dwellings in the vicinity of Thrapston Road on the north edge of Brampton

ON-C03(BA): Dwellings in the vicinity of Huntingdon Road on the east edge of Brampton


ON-C04(S): Dwellings in the vicinity of Stewart Close on the west edge of Brampton

ON-C05(S): Dwellings on the west edge of RAF Brampton

ON-N01(BA): Premier Inn, Brampton


ON-C02(BA): Dwellings in the vicinity of Thrapston Road on the north edge of Brampton

Section 3: A14 East Coast Main Line to Swavesey


ON-C06(S): Dwellings in the vicinity of Pear Tree Close


ON-C07(BA): Dwellings to the south of Fenstanton close to the existing A14

ON-N02(BA): Stagecoach, Fenstanton

ON-N03(BA): MAB General Insurance Services Ltd, Fenstanton


ON-C06(S): Dwellings in the vicinity of Pear Tree Close


ON-C07(BA): Dwellings to the south of Fenstanton close to the existing A14

ON-N02(BA): Stagecoach, Fenstanton

ON-N03(BA): MAB General Insurance Services Ltd, Fenstanton

Section 4: A14 Swavesey to Girton

Adverse significant effects:

ON-N04(S): New Close Business Park


ON-C16(BA): Dwellings (Hill Farm Cottages) in the vicinity of the existing A14

ON-N14(BA): Cambridge City Crematorium

Adverse significant effects:

ON-N04(S): New Close Business Park


ON-C16(BA): Dwellings (Hill Farm Cottages) in the vicinity of the existing A14

ON-N14(BA): Cambridge City Crematorium


Section 5: Cambridge Northern Bypass


ON-C17(BA): Dwellings in Girton alongside Cambridge Northern Bypass

ON-C18(BA): Dwellings at Blackwell Caravan Park


ON-C17(BA): Dwellings in Girton alongside Cambridge Northern Bypass

ON-C18(BA): Dwellings at Blackwell Caravan Park

Section 6: Huntingdon Improvements

Beneficial significant effects (approx. 2,500 dwellings):

Multiple beneficial significant effects on both residential communities and non-residential receptors:

ON-C09(BA) through ON-C13(BA) and ON-N05(BA) through ON-N13(BA)

Beneficial significant effects (approx. 2,500 dwellings):

Multiple beneficial significant effects on both residential communities and non-residential receptors:

ON-C09(BA) through ON-C13(BA) and ON-N05(BA) through ON-N13(BA)

Notes:

1) Each significant effect has been given a unique identification, for example ON-C04(S). The identification is explained in Appendix 14.4 (construction), Appendix 14.5 (operation) and Appendix 14.6 (operation) of the Environmental Statement Appendices (document reference 6.3) submitted as part of the DCO application.

Table 4.4: Details of increases between noise calculations for CHARM3a compared CHARM2 traffic data with reference to Figure 4.4

Detail highlight from Figure 5.4

Discussion

Detail #1

Alconbury

The noise level increases forecast through Alconbury as a result of the proposed scheme are around 1.5 dB greater with CHARM 3A data compared to CHARM 2 data. This is due to the increase in speed from 85 km/h to 110 km/h between the traffic models. Using the significance criteria in the ES, the forecast noise impacts with CHARM 3A data are not considered a significant effect. For the majority of Alconbury, the increase in noise (due to increase in traffic volumes and speeds compared to the ‘Do-Minimum’ scenario) would be minimised by the substantial increase in the height of the noise barriers from existing 2m barriers to 4m absorptive barriers with the proposed scheme.

Detail #2

A1 / Buckden Road Interchange

The noise level changes forecast at the small number of receptors in this location as a result of the proposed scheme are around 1 dB higher with CHARM 3A data compared to CHARM 2 data. This is due to the decrease in percentage of HGVs on the connecting slip roads between the A1 and Buckden Road in the ‘Do-Minimum’ scenario.

Conclusions

4.4.19 The information in Figure 4.4, Table 4.3 and Table 4.4 confirm no new likely significant noise effects for the assessment using CHARM3a data compared to the CHARM2 assessment reported in the ES.

4.4.20 The conclusions of the ES therefore remain valid.


WebTAG results

4.4.21 WebTAG noise valuation based on CHARM2 data, was £32.4 million (a positive number representing a net benefit). The equivalent valuation assuming CHARM3a data is £28.6 million.

4.5 Other environmental topics

Impact of CHARM3a compared to CHARM2 4.5.1 In addition to the detailed assessment of air quality and noise, screening of

environmental issues was undertaken to identify the likelihood of significant changes. This comprised a high level review by the relevant technical specialists of the following CHARM3a data, compared to CHARM2 as represented in the ES:

• review of percentage differences in terms of traffic flows per link;

• review of flow differences in vehicle numbers per link; and

• consideration of implications in respect of relevant threshold and criteria. 4.5.2 The results of this screening exercise indicated that the CHARM3a data would

not give rise to any likely significant effects additional to those set out in the ES.

4.6 Summary 4.6.1 The detailed assessment of CHARM3a data did not identify any significant

changes to air quality in AQMAs and no new likely significant effects in any modelled area compared to the ES results. Furthermore, there is no predicted risk of exceeding limit values on PCM links.

4.6.2 With regards to noise the CHARM3a assessment confirmed no new likely

significant effects for the assessment using CHARM3a data compared to the CHARM2 assessment reported in the ES.

4.6.3 High level screening of all other relevant environmental factors did not identify

any additional likely significant effects as a result of CHARM3a traffic data. 4.6.4 The conclusions of the ES remain valid in light of CHARM3a traffic data.


5 Economic case

5.1 Introduction Purpose and scope

5.1.1 The purpose of this section of the report is to provide an update of the

economic case for the scheme, as presented in the Case for the Scheme (document reference 7.1, section 5) submitted as part of the DCO application, as a result of CHARM3a. It presents the comparative anticipated benefits and disbenefits associated with the scheme and the scheme’s overall value for money.

Methodology

5.1.2 The method of assessment is the same as that used in the Case for the Scheme (document reference 7.1, section 5.2).

5.2 Monetised benefits 5.2.1 A comparison of the monetised economic, environmental and social benefits

of the scheme for both the Initial and Adjusted Benefit to Cost Ratio (BCR) is provided in Table 5.1.

Table 5.1: Summary of monetised benefits

Benefits

Monetised Value, m

Initial BCR Adjusted BCR

CH

AR

M2

CH

AR

M3a

CH

AR

M2

CH

AR

M3a

Economic Benefits

Business User Benefits

Travel Time £953.4 £687.1 £953.4 £687.1

Vehicle Operating Costs

£88.7 -£36.8 £88.7 -£36.8

Delays During Construction

-£45.9 -£49.0 -£45.9 -£49.0

Delays During Maintenance

£43.2 £45.4 £43.2 £45.4

Net Business User Benefits

£1,039.4 £646.7 £1,039.4 £646.7

Journey Time Reliability

- - £434.8 £480.2

Regeneration - - - -


Wider Impacts - - £76.7 £178.6

Environmental Benefits

Greenhouse Gas Emissions -£207.8 £119.5 -£207.8 £119.5

Noise £32.4 £28.6 £32.4 £28.6

Air Quality £2.6 £2.8 £2.6 £2.8

Social Benefits

Consumer – Commuting User Benefits

Travel Time £239.6 £189.6 £239.6 £189.6


-£7.0 £1.2 -£7.0 £1.2


-£11.5 -£13.5 -£11.5 -£13.5


£10.9 £12.5 £10.9 £12.5

Net Consumer – Commuter User Benefits

£232.0 £189.8 £232.0 £189.0

Consumer – Other User Benefits

Travel Time £640.5 £423.9 £640.5 £423.9


-£65.4 -£5.2 -£65.4 -£5.2


-£30.8 -£30.2 -£30.8 -£30.2


£29.0 £28.0 £29.0 £28.0

Net Consumer – Other User Benefits

£573.3 £416.5 £573.3 £416.5

Journey Time Reliability - - £426.5 £471.4

Accident Benefits £124.9 £44.6 £124.9 £44.6

Public Accounts Indirect Tax Revenues -£4.8 £19.9 -£4.8 £19.9

Total Present Value of Benefits £1,792.0 £1,229.4 £2,730.0 £2,359.6

Economic benefits

5.2.2 From Table 5.1 it can be seen that scheme would continue to deliver significant benefits to business users through reduced travel times. After accounting for impacts associated with delays during construction and maintenance and changes to vehicle operating costs, the combined monetised value of these benefits is forecast to be £646.7 million. The reduction in business user benefits is a result of changes to External to External growth assumptions as outlined in section 2.2.6 which have resulted in lower levels of growth and have therefore suppressed benefits.


5.2.3 Additional capacity delivered by the scheme would also continue to benefit

business users and transport service providers by providing greater journey time reliability, resulting in a monetised value of £480.2 million. The increase between CHARM2 and CHARM3a is a due to the lower levels of growth outlined above, which result in greater capacity and subsequently more predictable journey times.

5.2.4 The scheme would continue to unlock economic activity and contribute to

wider benefits. The monetised value of these wider benefits is forecast to be £178.6 million.

Environmental benefits 5.2.5 The monetised value of noise improvements is forecast to by £28.6 million.

5.2.6 The monetised value of air quality improvements is forecast to be £2.8 million.

5.2.7 The monetised value of greenhouse gas emissions is forecast to be -£119.5

million.

Social benefits 5.2.8 The scheme would deliver significant benefits to commuters and other users

through reduced travel times. After accounting for impacts associated with delays during construction and maintenance and changes to vehicle operating costs, the combined monetised value of these benefits is forecast to be £606.3 million. As with the reduction in business user benefits, the reduction in commuter and other user benefits is a result of changes to External to External growth assumptions.

5.2.9 Additional capacity delivered by the scheme would also benefit commuters and other users by providing greater journey time reliability, resulting in a monetised value of £471.4 million. As with the increase in business user benefits, this is due to the lower levels of growth.

5.2.10 The scheme would have a positive impact on road safety in the Cambridge-Huntingdon area leading to an overall reduction in accidents within the scheme study area. The decrease in accidents would lead to a saving of £44.6 million.

5.2.11 It should be noted that the significant reduction in accident benefits compared

to those produced using CHARM2 is predominantly a result of changes to the software used to appraise accident savings. As part of the revised economic parameters published by the Department for Transport in November 2014 changes were made to reflect the latest accident statistics for Great Britain. Without these changes to software parameters, the decrease in accidents would lead to a saving in the region of £100 million.


5.2.12 The scheme’s value for money is categorised, based on the BCR. A comparison of both the Initial and Adjusted BCR are provided in Table 5.2.

Table 5.2: Scheme Benefit Cost Ratio and value for money category

Monetised Value, m

Initial BCR Adjusted BCR

CHARM2 CHARM3a CHARM2 CHARM3a

Total Present Value of Benefits £1,792.0 £1,229.4 £2,730.0 £2,359.6

Costs

Operating Costs (Capital Costs of Maintenance)

-£139.5 -£140.0 -£139.5 -£140.0

Investment Costs £1,169.3 £1,169.0 £1,169.3 £1,169.0

Total Present Value of Costs £1,029.7 £1,029.0 £1,029.7 £1,029.0

Benefit Cost Ratio 1.7 1.2 2.7 2.3

Value for Money category Medium Low High High

5.2.13 The slight change in the Total Present Value of Costs between CHARM2 and

CHARM3a is due to a change in the current year of the appraisal (2014 and 2015 respectively), where the current year is the reference year against which discount rates to costs and benefits are made.

5.2.14 It should be noted that the BCR for the scheme does not include the benefits associated with planning gain arising from new developments that are considered to be dependent on the scheme. While these benefits are not normally included in the BCR calculation they can be used to determine scheme’s overall value for money.

Conclusions

5.2.15 While the Initial and Adjusted BCRs for the scheme have reduced from 1.7 to

1.2 and from 2.7 to 2.3 respectively, the conclusions of the Case for the Scheme (document reference 7.1) remain valid in that the scheme would remain high value for money.


6 March 2015 road traffic forecasts

6.1 Introduction 6.1.1 In March 2015 the Department for Transport (DfT) published updated road

traffic forecasts for England (RTF15). RTF15 is an update to road traffic forecasts published in July 2013 (Road Traffic Forecasts 2013) and is in response to stakeholder concerns around the DfT’s forecasts for significant traffic growth.

6.1.2 As outlined in section 2.2.6 of this report, CHARM3a External to External trip

growth for HGVs is based on the National Transport Model (NTM) Road Traffic Forecasts 2013 (RTF13). External to External trip growth for light vehicles, that is, cars and light goods vehicles (LGVs), is derived from forecasts from the National Trip End Model version 6.2 (NTEM 6.2), which remains unchanged.

6.1.3 Subsequently, to assess the impact of updated (2015) growth forecasts, the

External to External HGV growth assumptions in CHARM3a have been updated. CHARM3a External to External growth assumptions for light vehicles continue to be based on NTEM 6.2.

6.1.4 Unlike previous forecasts, RTF15 data have been formulated using a scenario-based approach. The 5 scenarios included in RTF15 are defined in Table 6.1.

Table 6.1: Road Traffic Forecasts 2015 scenario definitions

Scenario Trip rates Income relationship Macroeconomic

Scenario 1 Historic average Positive and declining Central

Scenario 2 Historic average Zero Central

Scenario 3 Extrapolated trend Positive and declining Central

Scenario 4 Historic average Positive and declining High oil, low GDP

Scenario 5 Historic average Positive and declining Low oil, high GDP

6.1.5 Scenario 1 is the closest equivalent to the assumptions underpinning the

RTF13 growth forecasts applied in CHARM3a and therefore it is this growth scenario that has been used to reforecast External to External HGV growth in the form of a CHARM3a+RTF15 sensitivity test.

6.2 CHARM3a+RTF15 traffic projections 6.2.1 Forecasts have been produced for 2020, which is the first full year that the

scheme is expected to open, and for 2035, which is a future year used to assess whether the design of the scheme will be able to accommodate future predicted traffic growth. The forecasts consider scenarios both without the


scheme (a ‘Do-Minimum’ scenario) and with the scheme (a ‘Do-Something’ scenario).

6.2.2 These forecasts reflect the best information currently available and are

intended to provide a forecast of the likely travel conditions on the A14 and surrounding road network, both with and without the proposed scheme.

Table 6.2: Comparison of 2-way AADT forecasts on major routes without scheme

Location CHARM3a CHARM3a+RTF15

2014 2020 2035 2014 2020 2035

A14 West of A1 41,600 45,300 51,600 41,600 45,200 51,500

A14 Spur East of A1(M)

42,100 46,000 53,300 42,100 45,900 53,300

A14 Through Huntingdon

72,700 80,400 90,300 72,700 80,200 90,300

A14 Huntingdon Southern Bypass

- - - 0 0 0


80,300 86,200 94,600 80,300 86,100 94,600

A14 Bar Hill to Girton

91,400 100,300 111,300 91,400 100,200 111,300

A14 Histon to Milton

64,300 76,200 85,800 64,300 76,100 85,800

A14 East of Milton

61,700 70,000 79,300 61,700 69,900 79,200

A1 North of Alconbury

69,600 73,900 81,800 69,600 73,900 81,700

A1 North of Brampton Hut

32,700 36,200 43,500 32,700 36,200 43,500

A1 South of Brampton Hut

35,600 39,300 45,700 35,600 39,300 45,700

A1 Near Buckden

43,400 47,000 52,000 43,400 47,000 52,000

M11 South of Girton

62,800 72,700 83,000 62,800 72,600 83,000

A428 Near Bourne Airfield

33,500 40,900 51,900 33,500 40,800 51,800

A1198 West of Hilton

10,400 11,500 14,200 10,400 11,500 14,100

A141 North of Huntingdon

28,700 29,400 29,500 28,700 29,400 29,600

Units: vehicles per day, rounded to nearest 100.


6.2.3 Table 6.2 shows 2-way AADT forecasts on major routes without the scheme to be identical for both CHARM3a and CHARM3a+RTF15 with the following exceptions:

• A14 East of Milton in 2020 (difference of -100 vehicles or -0.14%); and

• A141 North of Huntingdon in 2035 (difference of +100 vehicles or +0.34%).

Table 6.3: Comparison of 2-way AADT forecasts on major routes with scheme


2014 2020 2035 2014 2020 2035

A14 West of A1 41,600 47,300 55,700 41,600 47,200 55,600

A14 Spur East of A1(M)

42,100 21,000 24,600 42,100 21,000 24,600

A14 Through Huntingdon

72,700 11,900 14,600 72,700 11,900 14,600

A14 Huntingdon Southern Bypass

- 65,300 80,300 - 65,100 80,100


80,300 87,800 104,600 80,300 87,600 104,400

A14 Bar Hill to Girton

91,400 103,500 127,500 91,400 103,300 127,300

A14 Histon to Milton

64,300 81,700 97,400 64,300 81,600 97,400

A14 East of Milton

61,700 70,800 81,300 61,700 70,700 81,300

A1 North of Alconbury

69,600 74,500 83,600 69,600 74,500 83,500

A1 North of Brampton Hut

32,700 60,500 74,200 32,700 60,400 74,100

A1 South of Brampton Hut

35,600 72,600 86,900 35,600 72,500 86,800

A1 Near Buckden

43,400 47,700 53,300 43,400 47,700 53,300

M11 South of Girton

62,800 73,200 85,500 62,800 73,200 85,300

A428 Near Bourne Airfield

33,500 39,300 48,000 33,500 39,300 48,000

A1198 West of Hilton

10,400 12,400 15,100 10,400 12,400 15,100

A141 North of Huntingdon

28,700 28,300 28,900 28,700 28,300 28,900



6.2.4 Table 6.3 shows 2-way AADT forecasts on major routes with the scheme to be identical for both CHARM3a and CHARM3a+RTF15 with the following exceptions:

• A14 Bar Hill to Girton in 2020 (difference of -200 vehicles or -0.19%); and

• A1 North of Alconbury in 2035 (difference of -100 vehicles or +0.12%). Table 6.4: Comparison of 2-way AADT forecasts on local roads without scheme


2014 2020 2035 2014 2020 2035



10,800 8,600 11,700 10,800 8,600 11,800


5,700 6,000 7,400 5,700 6,000 7,400


16,200 17,000 18,800 16,200 17,000 18,800


15,300 15,800 18,500 15,300 15,800 18,500


15,900 17,600 20,800 15,900 17,600 20,800


9,700 10,500 11,200 9,700 10,500 11,200


7,500 6,800 7,500 7,500 6,800 7,600



14,600 14,600 14,900 14,600 14,600 14,900


10,400 11,100 12,500 10,400 11,100 12,500


23,300 23,100 23,200 23,300 23,100 23,200

High Street (through Over)

2,200 2,200 2,300 2,200 2,200 2,300


High Street (through Swavesey)

500 600 900 500 600 900


11,100 12,700 13,600 11,100 12,700 13,600


13,800 16,200 19,200 13,800 16,200 19,200


6,700 7,700 8,800 6,700 7,700 8,800

Elsworth Road (through Conington)

800 1,300 2,500 800 1,300 2,500

High Street (through Knapwell)

1,000 1,800 3,800 1,000 1,800 3,800

High Street (through Boxworth)

2,300 2,700 3,400 2,300 2,700 3,400


4,900 5,900 8,700 4,900 5,900 8,700


A603 Barton Road (east of M11)

13,700 14,100 17,400 13,700 14,100 17,400


16,100 18,300 21,000 16,100 18,300 21,000


10,800 11,000 13,500 10,800 11,000 13,500

Cambridge Road (through Girton)

5,300 5,900 8,900 5,300 5,900 8,900


18,900 20,900 23,900 18,900 20,900 23,900

B1049 Histon Road (south of A14)

16,400 22,100 26,400 16,400 22,100 26,500

A10 Ely Road (through Milton)

21,000 23,100 24,500 21,000 23,200 24,500


A1309 Milton Road (south of A14)

31,500 31,200 35,700 31,500 31,200 35,700

A10 Ely Road (past Waterbeach)

25,700 26,500 27,600 25,700 26,500 27,600


6.2.5 Table 6.4 shows 2-way AADT forecasts on local roads without the scheme to

be identical for both CHARM3a and CHARM3a+RTF15 with the following exceptions:

• B1043 Ermine Street (through Great Stukeley) in 2035 (difference of +100 vehicles or +0.85%);

• B1514 Thrapston Road (north of Brampton) in 2035 (difference of +100 vehicles or +1.33%); and

• A10 Ely Road (through Milton) in 2020 (difference of +100 vehicles or +0.43%).

Table 6.5: Comparison of 2-way AADT forecasts on local roads with scheme


2014 2020 2035 2014 2020 2035



10,800 8,400 11,300 10,800 8,400 11,300


5,700 6,100 7,200 5,700 6,100 7,200


16,200 14,500 16,400 16,200 14,500 16,400


15,300 6,700 8,700 15,300 6,700 8,700


15,900 23,100 25,300 15,900 23,100 25,300


9,700 9,700 9,600 9,700 9,700 9,600


7,500 4,000 4,300 7,500 4,000 4,300




14,600 13,900 14,100 14,600 13,900 14,100


10,400 11,100 12,600 10,400 11,100 12,500


23,300 22,800 22,600 23,300 22,800 22,600

High Street (through Over)

2,200 2,200 2,100 2,200 2,200 2,100

High Street (through Swavesey)

500 600 900 500 600 900


11,100 13,000 16,200 11,100 13,000 16,200


13,800 17,600 16,600 13,800 17,700 16,600


6,700 7,900 9,200 6,700 8,000 9,200

Elsworth Road (through Conington)

800 1,400 2,700 800 1,400 2,700

High Street (through Knapwell)

1,000 1,400 3,200 1,000 1,400 3,100

High Street (through Boxworth)

2,300 2,500 3,300 2,300 2,500 3,300


4,900 6,500 11,100 4,900 6,500 11,000


A603 Barton Road (east of M11)

13,700 14,300 17,000 13,700 14,300 17,000


16,100 18,100 20,000 16,100 18,100 20,000



10,800 12,400 17,400 10,800 12,400 17,300

Cambridge Road (through Girton)

5,300 4,900 6,900 5,300 4,900 6,900


18,900 22,200 24,000 18,900 22,200 24,000

B1049 Histon Road (south of A14)

16,400 22,700 26,400 16,400 22,700 26,500

A10 Ely Road (through Milton)

21,000 23,200 24,600 21,000 23,200 24,600

A1309 Milton Road (south of A14)

31,500 31,400 35,600 31,500 31,400 35,600

A10 Ely Road (past Waterbeach)

25,700 26,700 27,600 25,700 26,700 27,600


6.2.6 Table 6.5 shows 2-way AADT forecasts on local roads with the scheme to be identical for both CHARM3a and CHARM3a+RTF15 with the following exceptions:

• B1040 Somersham Road (north of St Ives) in 2035 (difference of -100 vehicles or -0.79%);

• B1040 Potton Road (north of Hilton) in 2020 (difference of +100 vehicles or +1.27%);

• High Street (through Knapwell) in 2035 (difference of -100 vehicles or -3.13%); and

• Scotland Road (through Dry Drayton) in 2035 (difference of -100 vehicles or -0.90%).

6.2.7 Table 6.2 to Table 6.5 inclusive show that updated road traffic forecasts for England published by the DfT in March 2015 have a negligible impact on traffic forecasts.

6.3 Operational assessment

6.3.1 As stated above, the difference between the CHARM3a+RTF15 traffic figures and CHARM3a traffic figures is negligible. However, a number of merge and diverge layouts throughout the scheme are sensitive to very minor changes in traffic flows and therefore an analysis of the required merge and diverge layouts (for CHARM3a+RTF15 flows) has been undertaken. All merge and


diverge layouts would be the same with CHARM3a and CHARM3a+RTF15 traffic flows with the exception of:

• Histon junction westbound diverge: The CHARM 3a traffic figures require a Type A taper diverge. The CHARM3a+RTF15 traffic flows increase the peak hour flows marginally to require a Type B parallel diverge. The peak hour turning flows increase to 1226 vehicles per hour (vph) in the PM peak: only 26 vph above the threshold of 1200 vph. A Type A taper diverge is required to avoid impacting in the adjacent Orchard Park development and therefore it is considered that a departure from standard for a Type A diverge would be entirely justified in this instance.

• Histon junction westbound merge: The CHARM3a traffic figures require a Type C ghost island merge, however a Type B parallel merge is proposed to avoid impacting on Woodhouse Farm, requiring a departure from standards. The CHARM3a+RTF15 traffic flows increase the peak hour flows marginally to require a Type F lane gain with ghost island merge and a 4 lane mainline. The peak hour flows on the mainline downstream of the merge would increase to 4898 vph in the PM peak: only 98 vph above the threshold of 4800 vph for three lanes on the mainline. It is not proposed to provide an additional mainline lane and therefore a lane gain merge arrangement cannot be justified economically. However, it is considered that the proposed arrangement would be sufficient for the majority of the life of the scheme. Therefore it is considered that a departure from standard for a Type B diverge would be entirely justified in this instance.

• A14 westbound to M11 southbound diverge: The CHARM3a traffic figures require a Type B parallel diverge with a 2 lane slip road. The proposed layout is a Type B parallel diverge with a 1 lane slip road, due to constraints of existing structures at Girton Interchange and therefore a departure from standard is required. The CHARM3a+RTF15 traffic flows increase the peak hour flows marginally to require a Type D ghost island at lane drop diverge. The peak hour turning flows increase from 1282 vph (CHARM3a) to 1379 vph (CHARM3a+RTF15), both slightly above the threshold of 1200vph for a single lane slip road. It is not proposed to provide an additional lane on the slip road and therefore a departure from standard would still be required at this location.

6.4 Environmental assessment

6.4.1 High level assessments of air quality, noise and other relevant environmental topics were undertaken using CHARM3a+RTF15 traffic data (referred to as RTF15). These assessments were based on traffic difference plots, which provide an analysis of differences between CHARM3a+RTF15 and CHARM3a traffic forecasts, to identify the possibility of likely significant changes to the ES conclusions.


Air Quality

6.4.2 For the RTF15 assessment, a high level review of the plots showing changes to traffic flow impacts was undertaken. The study area for the RTF15 review considered the whole traffic network. Particular focus was given to the main areas of concern, for example, AQMAs.

6.4.3 The results of the change plots showing the percentage difference in traffic

flows with the RTF15 forecasts indicated there is very little impact. Given that only very minor differences are observed between the CHARM3a+RTF15 data and the CHARM3a data, the conclusions from the detailed modelling of CHARM3a data remain valid. Therefore the conclusions within the ES also remain valid. Noise

6.4.4 For the RTF15 assessment, a high level review was undertaken based on plots showing changes in traffic flows which were used to identify any areas of potentially significant difference.

6.4.5 The summary of traffic flow change plots showed that RTF15 would result in very minor changes in traffic flows – specifically slight decreases in traffic flows across the entire study area in the with-scheme scenario relative to the CHARM2 data. This would mean that the RTF15 data would not result in any increases in adverse noise impacts as a result of the scheme.

6.4.6 The conclusions of the ES therefore remain valid.

Other topics

6.4.7 A high level environmental review was undertaken, covering other topics potentially affected by changes in traffic flows. The aim was to identify the likelihood of significant changes between anticipated environmental impacts associated with CHARM2 and RTF15, and to consider if this could give rise to likely significant effects in addition to those described in the ES.

6.4.8 The review did not identify any likely significant changes and concluded that

no additional significant environmental effects were likely as a result of CHARM3A+RTF15 traffic data.

Overall environmental findings

6.4.9 In regards to air quality, the high level assessment undertaken for RTF15 indicated very little impact.

6.4.10 In regards to noise, RTF15 would not result in any increases in adverse noise

impacts as a result of the scheme. 6.4.11 High level screening of all other relevant environmental factors did not identify

any likely additional significant effects as a result of RTF15.


6.4.12 The conclusions of the ES remain valid in light of RTF15. 6.4.13 The results of the change plots showing the percentage difference in traffic

flows with the RTF15 forecasts indicated there is very little impact. Given that only very minor differences are predicted between the CHARM3a+RTF15 data and the CHARM3a data it can be assumed the conclusions from the detailed modelling of CHARM3a data remain valid. Therefore the conclusions within the ES also remain valid.

6.5 Economic case 6.5.1 A high level assessment has been carried out to compare the impact of March

2015 road traffic forecasts on the economic case for the scheme against the revised CHARM3a economic case presented in section 5.

6.5.2 The assessment was based on a comparison of TUBA17 (Transport Users Benefit Appraisal) outputs for CHARM3a+RTF15 against CHARM3a TUBA outputs, which were used to ascertain the impact of RTF15 on the Initial BCR outlined in section 5 of this report.

6.5.3 The result of this assessment was a reduction in Present Value of Benefits (refer to Table 5.1 and Table 5.2) of around 1% compared against those reported for CHARM3a in section 5 of this report. Consequently, the Initial BCR for the scheme using CHARM3a+RTF15 data would remain at 1.2.

6.5.4 The assessment concluded that that the conclusions outlined in section 5.2.15

of this report in relation to CHARM3a remain valid and that the scheme would remain high value for money in response to CHARM3a+RTF15 data.

17

TUBA is the Department for Transport’s industry-standard tool for undertaking economic appraisal in accordance with guidelines published in WebTAG Unit A1.


7 Conclusions

7.1 Impact of traffic modelling update 7.1.1 This report has provided detail on the update made to the Cambridge to

Huntingdon A14 Road Model (CHARM) between December 2014 and spring 2015 and the subsequent impact on the assessment of the scheme. Impact of update on traffic projections

7.1.2 Overall the updated model (CHARM3a) has resulted in lower traffic forecasts on major routes and that this can be attributed to lower External to External growth assumptions. .

7.1.3 On local roads CHARM3a traffic forecasts are similar or lower than CHARM2 traffic forecasts reported in the Transport Assessment (document reference 7.2).

7.1.4 Lower External to External growth assumptions have resulted in greater capacity on the A14 and other strategic routes for local traffic. As a result, there is a general increase in the volume of local traffic entering and exiting the A14 at junctions in forecast years.

7.1.5 In Cambridge CHARM3a shows very similar impacts on radial routes as forecast by CHARM2 but for a slightly higher reduction in the 2035 PM peak (-5% compared to a CHARM2 total of -4%).

7.1.6 In Huntingdon CHARM3a shows similar impacts on radial routes as forecast by CHARM2.

Impact of update on operational assessments

7.1.7 For the majority of junctions, CHARM3a operational assessments are similar

to CHARM2 operational assessments reported in the Transport Assessment (document reference 7.2) in both the with and without scheme scenarios.

7.1.8 CHARM3a assessments show that the majority of junctions are forecast to operate well within capacity with the exception of the Bar Hill / Local Access Road junction, Histon junction, Milton junction, and the Brampton Road / Edison Bell Way junction, which are forecast to be operating above capacity in 2035. This mirrors the CHARM2 assessment reported in the Transport Assessment (document reference 7.2).

7.1.9 Additional sensitivity testing in relation to a high development scenario, which allows for full build out of development at Northstowe to 10,000 homes has been carried out. The results of this sensitivity testing show that junctions with layouts which suit CHARM3a would operate within capacity, albeit at higher levels of saturation, with no further modifications necessary.


Impact of update on link capacity assessments

7.1.10 CHARM3a link capacity assessments show that the majority of links are forecast to see increased capacity in comparison to CHARM2 as a result of reduced traffic flows.

7.1.11 CHARM3a assessments indicate that the A14 between Girton Interchange and Milton junction would experience capacity issues related to weaving flows by 2035, which mirrors the CHARM2 assessment reported in the Transport Assessment (document reference 7.2).

Impact of update on merge and diverge assessments

7.1.12 CHARM3a merge and diverge assessments show no change to the CHARM2 assessment reported in the Transport Assessment (document reference 7.2), with the exception of the A14/A1307/M11 eastbound diverge at Girton Interchange and the A14 Histon westbound diverge. However, in both instances, modifications can be made within the limits of deviation defined in the DCO that would resolve capacity issues at these locations. Impact of update on environmental assessment

7.1.13 CHARM3a assessments did not identify any significance changes to air

quality compared to the CHARM2 assessment reported in the Environmental Assessment (document reference 6.1).

7.1.14 Similarly, CHARM3a assessments did not identify any new likely significant

effects in relation to noise. 7.1.15 High level screening of all other relevant environmental factors did not identify

any additional significant effects as a result of the CHARM3a update.

7.1.16 The conclusions of the Environmental Assessment (document reference 6.1) submitted as part of the DCO application in December 2014 remain valid. Impact of update on the economic case

7.1.17 While the Initial and Adjusted BCRs for the scheme have reduced from 1.7 to 1.2 and from 2.7 to 2.3 respectively, the conclusions of the Case for the Scheme (document reference 7.1) remain valid in that the scheme would remain high value for money.

7.2 Impact of March 2015 road traffic forecasts

7.2.1 This report has also provided detail on updated road traffic forecasts published by the Department for Transport in March 2015 (RTF15) and the subsequent impact on assessment of the scheme

7.2.2 RTF15 has had a negligible effect on traffic forecasts.


7.2.3 All merge and diverge layouts would be the same with CHARM3a and CHARM3a+RTF15 traffic flows with the exception of:

• Histon Junction Westbound diverge

• Histon Junction Westbound merge

• A14 westbound to M11 southbound diverge

7.2.4 Proposed modifications to the above junctions can be accommodated within the limits of deviation defined in the DCO.

7.2.5 RTF15 has had little effect on air quality and would not result in any increases in adverse noise impacts as a result of the scheme. High level screening of all other relevant environmental factors did not identify any likely additional significant effects as a result of RTF15.

7.2.6 The conclusions of the ES remain valid in light of RTF15.

7.2.7 RTF15 has resulted in a reduction in Present Value of Benefits (refer to Table 5.1 and Table 5.2) of around 1% compared against those reported for CHARM3a. Consequently, the Initial BCR for the scheme using CHARM3a+RTF15 data would remain at 1.2.

7.2.8 The conclusions of the Case for the Scheme (document reference 7.1) remain

valid in that the scheme would remain high value for money.


Appendix A


This appendix summarises the results of the operational assessments undertaken based on the updated traffic forecasts from CHARM3a. It is considered that the model predictions for future years are likely to be an overestimation since, in practice, unconstrained traffic growth during the peak hours is unlikely to occur as a result of local and national sustainable travel and demand management measure policies. Consequently the results of the operational assessments represent a conservative view of likely junction performance. Ellington Junction North Roundabout The Ellington junction north roundabout is a new junction and therefore no ‘Do-Minimum’ (without scheme) operational assessment has been undertaken. The results of the ‘Do-Something’ (with scheme) operational assessment undertaken for the Ellington junction north roundabout are summarised in Table A.1. Table A.1: Ellington Junction North Roundabout Capacity Assessment (‘Do-Something’ scenario)

Junction Arm

2020 ‘Do-Something’ Scenario 2035 ‘Do-Something’ Scenario

AM Peak Hour (0800-0900)

PM Peak Hour (1700-1800)



RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

Old A14 (east) WB On-slip

62% 2 74% 3 69% 2 83% 5

Bridge 0% 0 0% 0 0% 0 0% 0

A14 (west) EB Off-Slip

41% 1 32% 1 46% 1 35% 1

Local Access Road

12% 0 13% 0 15% 0 14% 0

The operational assessment indicates that all arms of the Ellington junction north roundabout are forecast to operate well within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035.

Ellington Junction South Roundabout The Ellington junction south roundabout is a new junction and therefore no ‘Do-Minimum’ (without scheme) operational assessment has been undertaken. The results of the ‘Do-Something’ (with scheme) operational assessment undertaken for the Ellington junction south roundabout are summarised in Table A.2.


Table A.2: Ellington Junction South Roundabout Capacity Assessment (‘Do-Something’ scenario)

Junction Arm






RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

Bridge 43% 1 50% 1 49% 1 56% 1

Local Access Road

0% 0 0% 0 0% 0 0% 0

A14 (west) On-Slip

Exit Arm Exit Arm Exit Arm Exit Arm

The operational assessment indicates that all arms of the Ellington junction south roundabout are forecast to operate well within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035. Brampton Road / Buckden Road Roundabout The Brampton Road / Buckden Road roundabout is a new junction and therefore no ‘Do-Minimum’ (without scheme) operational assessment has been undertaken. The results of the ‘Do-Something’ (with scheme) operational assessment undertaken for the Brampton Road / Buckden Road roundabout junction are summarised in Table A.3. Table A.3: Brampton Road / Buckden Road Roundabout Capacity Assessment (‘Do-Something’ scenario)

Junction Arm






RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

Buckden Road (east)

24% 0 37% 1 21% 0 32% 1

A1 SB Slips 1% 0 1% 0 2% 0 1% 0

A1 NB Slips 36% 1 31% 0 35% 1 28% 0

The operational assessment indicates that all arms of the Brampton Road / Buckden Road roundabout are forecast to operate well within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035.


A14/A1198 Junction North Roundabout The A14/A1198 junction north roundabout is a new junction and therefore no ‘Do-Minimum’ (without scheme) operational assessment has been undertaken. The results of the ‘Do-Something’ (with scheme) operational assessment undertaken for the A14/A1198 junction north roundabout are summarised in Table A.4. Table A.4: A14/A1198 Junction North Roundabout Capacity Assessment (‘Do-Something’ scenario)

Junction Arm






RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

A14 (west) 23% 0 21% 0 28% 0 26% 0

A1198 (north) 37% 1 29% 0 45% 1 38% 1

Local Access Road

0% 0 0% 0 0% 0 0% 0

A1198 (south)

22% 0 22% 0 27% 0 23% 0

The operational assessment indicates that all arms of the A14/A1198 junction north roundabout are forecast to operate well within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035. A14/A1198 Junction South Roundabout The A14/A1198 junction south roundabout is a new junction and therefore no ‘Do-Minimum’ (without scheme) operational assessment has been undertaken. The results of the ‘Do-Something’ (with scheme) operational assessment undertaken for the A14/A1198 junction south roundabout are summarised in Table A.5. Table A.5: A14/A1198 Junction South Roundabout Capacity Assessment (‘Do-Something’ scenario)

Junction Arm






RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

A1198 (north) 51% 1 41% 1 59% 1 51% 1

A14 (east) 0% 0 0% 0 0% 0 0% 0

A1198 (south)

28% 0 34% 1 37% 1 40% 1

Local Access Road

0% 0 0% 0 0% 0 0% 0


A14 (west) On-Slip


The operational assessment indicates that all arms of the A14/A1198 junction south roundabout are forecast to operate well within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035. Swavesey Junction North Roundabout The Swavesey junction north roundabout is a new junction and therefore no ‘Do-Minimum’ (without scheme) operational assessment has been undertaken. The results of the ‘Do-Something’ (with scheme) operational assessment undertaken for the Swavesey junction north roundabout are summarised in Table A.6. Table A.6: Swavesey Junction North Roundabout capacity assessment (‘Do-Something’ scenario)

Junction Arm






RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

Bucking Way Rd

52% 1 49% 1 79% 4 70% 2

A14 EB Slips 14% 0 13% 0 18% 0 28% 0

Bridge 41% 1 34% 1 50% 1 40% 1

Local Access Road

66% 2 47% 1 79% 4 65% 2

The operational assessment indicates that all arms of the Swavesey junction north roundabout are forecast to operate well within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035. Swavesey Junction South Roundabout The Swavesey junction south roundabout is a new junction and therefore no ‘Do-Minimum’ (without scheme) operational assessment has been undertaken. The results of the ‘Do-Something’ (with scheme) operational assessment undertaken for the Swavesey junction south roundabout are summarised in Table A.7.


Table A.7: Swavesey Junction South Roundabout Capacity Assessment (‘Do-Something’ scenario)

Junction Arm






RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

Bridge Link 17% 0 22% 0 24% 0 27% 0

A14 Off-Slip 49% 1 70% 2 61% 2 69% 2

Link to Services

39% 1 35% 1 54% 1 43% 1

Local Access Road

0% 0 0% 0 0% 0 0% 0

A14 West On-Slip


The operational assessment indicates that all arms of the Swavesey junction south roundabout are forecast to operate well within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035. Swavesey junction services roundabout The results of the ‘Do-Minimum’ (without scheme) operational assessment undertaken for the Swavesey junction services roundabout are summarised in Table A.8. Table A.8: Swavesey junction services roundabout capacity assessment (‘Do-Minimum’ scenario)

Junction Arm

2020 ‘Do-Minimum’ Scenario 2035 ‘Do-Minimum’ Scenario





RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

Bridge 29% 0 43% 1 22% 0 32% 1

A14 Slips 29% 0 35% 1 31% 0 35% 1

Cambridge Services

19% 0 16% 0 24% 0 21% 0

High Street Boxworth

15% 0 10% 0 19% 0 15% 0

The operational assessment indicates that all arms of the Swavesey junction services roundabout are forecast to operate well within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035.


The results of the ‘Do-Something’ (with scheme) operational assessment undertaken for the Swavesey junction services roundabout are summarised in Table A.9. Table A.9: Swavesey Junction Services Roundabout Capacity Assessment (‘Do-Something’ scenario)

Junction Arm






RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

Link Road 12% 0 17% 0 17% 0 21% 0

A14 Off-Slip 22% 0 28% 0 27% 0 41% 1

Cambridge Services

21% 0 18% 0 26% 0 25% 0

High Street (Boxworth)

17% 0 9% 0 22% 0 12% 0

The operational assessment indicates that all arms of the Swavesey junction services roundabout are forecast to operate well within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035. Swavesey Junction Anderson Road Roundabout The Swavesey junction Anderson Road roundabout is a new junction and therefore no ‘Do-Minimum’ (without scheme) operational assessment has been undertaken. The results of the ‘Do-Something’ (with scheme) operational assessment undertaken for the Swavesey junction Anderson Road roundabout are summarised in Table A.10. Table A.10: Swavesey Junction Anderson Road Roundabout Capacity Assessment (‘Do-Something’ scenario)

Junction Arm






RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

Bucking Way Road (north)

39% 1 41% 1 48% 1 55% 1

Anderson Road (east)

1% 0 1% 0 1% 0 4% 0

Bucking Way Road (south)

14% 0 17% 0 21% 0 22% 0

Link Road 33% 1 33% 1 37% 1 47% 1


The operational assessment indicates that all arms of the Swavesey junction Anderson Road roundabout are forecast to operate well within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035. Bar Hill Junction Main Roundabout The Bar Hill junction main roundabout is a new junction and therefore no ‘Do-Minimum’ (without scheme) operational assessment has been undertaken. The results of the ‘Do-Something’ (with scheme) operational assessment undertaken for the Bar Hill junction main roundabout are summarised in Table A.11. Table A.11: Bar Hill Junction Main Roundabout Capacity Assessment (‘Do-Something’ scenario)

Junction Arm






RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

A14 Off-Slip (west)

18% 0 27% 0 35% 1 53% 1

Hatton's Road

20% 0 14% 0 28% 0 23% 0

A14 (east) Slips

18% 0 43% 1 46% 1 69% 2

B1050 (south)

30% 0 56% 1 42% 1 85% 5

The operational assessment indicates that all arms of the Bar Hill junction main roundabout are forecast to operate well within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035. Bar Hill Junction South Roundabout The results of the ‘Do-Minimum’ (without scheme) operational assessment undertaken for the Bar Hill junction south roundabout are summarised in Table A.12. Table A.12: Bar Hill Junction South Roundabout Capacity Assessment (‘Do-Minimum’ scenario)

Junction Arm






RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

Bridge 81% 4 28% 0 101% 29 35% 1


A14 Off-Slip 50% 1 92% 10 66% 2 94% 12

Golf Course 9% 0 12% 0 11% 0 15% 0

Crafts Way 43% 1 25% 0 51% 1 27% 0

Saxon Way 39% 1 95% 13 43% 1 106% 47

The operational assessment indicates that the junction would be approaching capacity by 2020 and would be operating above capacity by 2035. The results of the ‘Do-Something’ (with scheme) operational assessment undertaken for the Bar Hill junction south roundabout is summarised in Table A.13. Table A.13: Bar Hill Junction South Roundabout Capacity Assessment (‘Do-Something’ scenario)

Junction Arm






RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

From Bar Hill Main

41% 1 42% 1 45% 1 44% 1

Local Access 5% 0 4% 0 5% 0 5% 0

Crafts Way 31% 1 16% 0 33% 1 17% 0

Saxon Way 35% 1 70% 2 37% 1 77% 3

The operational assessment indicates that all arms of the Bar Hill junction south roundabout are forecast to operate well within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035. B1050 / Local Access Road Junctions The B1050 / local Access Road junctions (north and south) at Bar Hill are new junctions and therefore no ‘Do-Minimum’ (without scheme) operational assessment has been undertaken. The results of the ‘Do-Something’ (with scheme) operational assessments undertaken for the B1050 / local access road junction (north) is summarised in Table A.14.


Table A.14: B1050 / Local Access Road Junction (North) Capacity Assessment (‘Do-Something’ scenario)

Junction Arm






RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

Hatton’s Road (north)

59% 18 36% 8 84% 48 66% 23

Link Road 40% 3 50% 5 90% 12 80% 12

Hatton’s Road (south)

43% 5 50% 13 65% 13 70% 31

The operational assessment indicates that all arms of the B1050 / local access road junction (north) are forecast to operate within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in 2020 and would be approaching capacity by 2035. The results of the ‘Do-Something’ (with scheme) operational assessments undertaken for the B1050 / local access road junction (north) is summarised in Table A.14. Table A.15: B1050 / Local Access Road Junction (South) Capacity Assessment (‘Do-Something’ scenario)

Junction Arm






RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

Link Road 61% 7 51% 5 82% 14 84% 12

LAR (east) 43% 4 43% 4 83% 12 84% 13

LAR (west) 34% 3 14% 1 33% 4 54% 7

The operational assessment indicates that all arms of the B1050 / local access road junction (south) are forecast to operate within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035. Dry Drayton Junction North Roundabout The Dry Drayton junction north roundabout is a new junction and therefore no ‘Do-Minimum’ (without scheme) operational assessment has been undertaken. The results of the ‘Do-Something’ (with scheme) operational assessment undertaken for the Dry Drayton junction north roundabout are summarised in Table A.16.


Table A.16: Dry Drayton Junction North Roundabout Capacity Assessment (‘Do-Something’ scenario)

Junction Arm






RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

Huntingdon Road (west)

34% 1 22% 0 47% 1 46% 1

Dry Drayton Road

39% 1 30% 0 53% 1 45% 1

Farm Access 0% 0 0% 0 0% 0 0% 0

Oakington Road

20% 0 25% 0 42% 1 45% 1

The operational assessment indicates that all arms of the Dry Drayton junction north roundabout are forecast to operate within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035. Dry Drayton Junction South Roundabout The Dry Drayton junction south roundabout is a new junction and therefore no ‘Do-Minimum’ (without scheme) operational assessment has been undertaken. The results of the ‘Do-Something’ (with scheme) operational assessment undertaken for the Dry Drayton junction south roundabout are summarised in Table A.17. Table A.17: Dry Drayton Junction South Roundabout Capacity Assessment (‘Do-Something’ scenario)

Junction Arm






RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

Oakington Road (west)

28% 0 28% 0 49% 1 47% 1

Oakington Road (east)

36% 1 18% 0 47% 1 35% 1

Local Access Road (south)

6% 0 10% 0 9% 0 19% 0

The operational assessment indicates that all arms of the Dry Drayton junction south roundabout are forecast to operate within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035.


Local Access Road Junction West Roundabout The local access road junction west roundabout at Girton Interchange is a new junction and therefore no ‘Do-Minimum’ (without scheme) operational assessment has been undertaken. The results of the ‘Do-Something’ (with scheme) operational assessment undertaken for the local access road junction west roundabout are summarised in Table A.18. Table A.18: Local Access Road Junction West Roundabout Capacity Assessment (‘Do-Something’ scenario)

Junction Arm






RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

A14 On-Slip Exit Arm Exit Arm Exit Arm Exit Arm

Local Access Road (east)

29% 0 42% 1 51% 1 52% 1

Local Access Road (west)

27% 0 30% 0 46% 1 49% 1

The operational assessment indicates that all arms of the local access road junction west roundabout are forecast to operate within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035. Local Access Road Junction East Roundabout The local access road junction east roundabout at Girton Interchange is a new junction and therefore no ‘Do-Minimum’ (without scheme) operational assessment has been undertaken. The results of the ‘Do-Something’ (with scheme) operational assessment undertaken for the local access road junction east roundabout junction are summarised in Table A.19. Table A.19: Local Access Road Junction East Roundabout Capacity Assessment (‘Do-Something’ scenario)

Junction Arm






RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

RFC

(%)

Queue

(vehs)

A14 Off-Slip 65% 2 48% 1 75% 3 85% 5

Local Access Road (east)

34% 1 59% 1 67% 2 73% 3

Local Access Road (west)

14% 0 8% 0 19% 0 18% 0


The operational assessment indicates that all arms of the local access road junction east roundabout are forecast to operate within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035. Histon Junction The results of the ‘Do-Minimum’ (without scheme) operational assessment undertaken for the Histon (signalised) junction are summarised in Table A.20. Table A.20: Histon Junction Capacity Assessment (‘Do-Minimum’ scenario)

Junction Arm






DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

A14 EB Off-Slip

E 75% 38 106% 68 83% 45 98% 57

C 66% 26 66% 17 65% 31 65% 19

B1049 Bridge Road

E 71% 32 69% 27 68% 31 69% 32

C 66% 28 54% 30 76% 31 69% 31

A14 WB Off-Slip

E 83% 22 43% 16 82% 21 61% 16

C 74% 35 65% 28 82% 53 70% 35

Cambridge Road

E 55% 27 108% 185 132% 307 136% 436

C 35% 10 41% 15 19% 6 41% 19

Cycle Time (secs) 118 118 118 118

Notes:

E = Entry, C = Circulatory

The operational assessment indicates that the junction is forecast to operate within capacity in the AM peak hour and marginally in excess of capacity in the PM peak hour in 2020. By 2035, the junction is forecast to be operating well in excess of capacity in both peak hours, with an average DoS of 132% in the AM peak hour and 136% in the PM peak hour on the Cambridge Road approach. All other approaches are forecast to operate within capacity, although the A14 EB off-slip has an average DoS of 98%. The results of the ‘Do-Something’ (with scheme) operational assessment undertaken for the Histon (signalised) junction are summarised in Table A.21.


Table A.21: Histon Junction Capacity Assessment (‘Do-Something’ scenario)

Junction Arm


AM Peak Hour

(0800-0900)

PM Peak Hour

(1700-1800)

AM Peak Hour

(0800-0900)

PM Peak Hour

(1700-1800)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

A14 EB Off-

Slip

E 71% 30 72% 22 85% 40 79% 27

C 66% 24 65% 17 61% 36 65% 27

B1049

Bridge Road

E 77% 30 56% 18 89% 42 60% 18

C 66% 29 61% 26 72% 32 67% 34

A14 WB

Off-Slip

E 82% 24 44% 19 83% 23 62% 24

C 76% 28 72% 44 83% 31 70% 33

Cambridge

Road

E 52% 24 111% 213 132% 316 131% 362

C 60% 18 48% 18 27% 7 46% 20

Cycle Time (secs) 118 118 112 112

Notes:


The operational assessment indicates that all arms of the Histon signalised junction are forecast to operate within capacity (DoS less than or equal to 85%) with the exception the entry from the B1049 Cambridge Road. Whilst one arm of the junction is expected to operate above capacity, the junction as a whole operates better, or no worse, than the ‘Do-Minimum’ scenario (without the scheme) both time periods in both 2020 and 2035. Milton Junction The results of the ‘Do-Minimum’ (without scheme) operational assessment undertaken for the Milton (signalised) junction are summarised in Table A.22. Table A.22: Milton Junction Capacity Assessment (‘Do-Minimum’ scenario)

Junction Arm






DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

A14 EB Off-Slip

E 105% 170 129% 130 114% 228 139% 150

C 49% 11 73% 26 60% 9 70% 27

A10 E 186% 362 71% 19 210% 446 70% 21

C 61% 28 70% 21 63% 27 65% 16

Cambridge E 55% 2 54% 2 68% 5 53% 2


Road C 42% 5 41% 8 41% 5 38% 9

A14 WB Off-Slip

E 122% 165 60% 16 121% 152 55% 17

C 67% 33 54% 22 67% 26 52% 19

A1309 E 38% 8 90% 154 32% 8 116% 346

C 28% 18 66% 27 37% 20 51% 23

Cycle Time (secs) 110 110 110 110

Notes:


The operational assessment indicates that the junction is forecast to operate in excess of capacity in both the AM and PM peak hours in 2020 and 2035. In the 2020 PM peak hour, the A1309 entry is forecast to have an average DoS of 90%, however the modelling shows a maximum DoS of 127% on the outside lane on this approach. The results of the ‘Do-Something’ (with scheme) operational assessment undertaken for the Milton (signalised) junction are summarised in Table A.23.

Table A.23: Milton Junction Capacity Assessment (‘Do-Something’ scenario)

Junction Arm






DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

A14 EB Off-Slip

E 100% 129 73% 20 111% 209 71% 26

C 37% 5 80% 25 42% 15 76% 43

A10 E 101% 100 73% 25 106% 126 63% 27

C 46% 15 64% 31 50% 18 69% 41

Cambridge Road

E 42% 2 45% 2 66% 3 41% 2

C 44% 8 42% 15 46% 12 42% 17

A14 WB Off-Slip

E 78% 22 57% 11 77% 24 55% 14

C 74% 36 57% 19 75% 48 51% 29

A1309 E 29% 27 84% 33 32% 30 85% 37

C 43% 9 68% 126 50% 11 65% 122

Cycle Time (secs) 84 84 110 110

Notes:


The operational assessment indicates that all arms of the Milton (signalised) junction are forecast to operate within capacity (DoS less than or equal to 85%) with the exception of the entry lanes from the A14 eastbound off-slip and the A10 in 2020 and 2035. Whilst two arms of the junction are expected to operate above capacity, the


junction is forecast to better, or no worse, than in the ‘Do-Minimum’ scenario (without the scheme) across both time periods in both 2020 and 2035. Views Common Junction Roundabout The Views Common junction roundabout in Huntingdon is a new junction and therefore no ‘Do-Minimum’ (without scheme) operational assessment has been undertaken. The results of the ‘Do-Something’ (with scheme) operational assessment undertaken for the Views Common junction roundabout are summarised in Table A.24. Table A.24: Views Common Junction Roundabout Capacity Assessment (‘Do-Something’ scenario)

Junction Arm






RFC (%)

Queue (vehs)

RFC (%)

Queue (vehs)

RFC (%)

Queue (vehs)

RFC (%)

Queue (vehs)

Old A14 (north)

31% 0 19% 0 40% 1 22% 0

Local Access 0% 0 0% 0 0% 0 0% 0

Old A14 (south)

25% 0 40% 1 24% 0 51% 1

The operational assessment indicates that all arms of the Views Common junction roundabout are forecast to operate within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035. Short queues are forecast even though the traffic movements are unopposed at this junction. These queues are the result of vehicles slowing down to negotiate the junction and as such would be transient in nature.

Huntingdon Town Centre The network of junctions in Huntingdon town centre that would be affected by the scheme have been assessed in a single operational model. The results of the assessment for each individual junction are presented below. Hinchingbrooke Road / Views Common Link Junction The results of the ‘Do-Minimum’ (without scheme) operational assessment undertaken for the Hinchingbrooke Road / Views Common Link junction are summarised in Table A.25.


Table A.25: Hinchingbrooke Road / Views Common Link Junction Capacity Assessment (‘Do-Minimum’ scenario)

Junction Arm






DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

Hinchingbrooke Road (west)

22% 2 40% 4 25% 2 47% 6

Hinchingbrooke Road (east)

16% 1 9% 1 19% 2 11% 1

Underpass 39% 1 29% 0 53% 1 31% 0

Cycle Time (secs)

90

The operational assessment indicates that all arms of the Hinchingbrooke Park Road / Views Common Link junction are forecast to operate within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035. It is expected that slow moving queues of traffic on Brampton Road from the junction with Edison Bell Way may block back on to Hinchingbrooke Park Road and extend past this junction in the peak hours. This would result in worse performance than the operational assessment suggests, potentially leading to longer queues and delays. The results of the ‘Do-Something’ (with scheme) operational assessment undertaken for the Hinchingbrooke Road / Views Common Link junction are summarised in Table A.26. Table A.26: Hinchingbrooke Road / Views Common Link Junction Capacity Assessment (‘Do-Something’ scenario)

Junction Arm






DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

Hinchingbrooke Park Road (west)

46% 10 59% 17 51% 11 60% 19

Views Common Link

37% 12 34% 9 52% 18 47% 12

Hinchingbrooke Park Road (east)

0% 0 0% 0 0% 0 0% 0

Underpass 59% 4 61% 8 75% 8 72% 11

Cycle Time (secs)

120


The operational assessment indicates that all arms of the Hinchingbrooke Road / Views Common Link junction are forecast to operate within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035. Again, it is expected that slow moving queues of traffic on Brampton Road from the junction with Edison Bell Way may block back on to Hinchingbrooke Park Road and extend past this junction in the peak hours. This would result in worse performance than the operational assessment suggests. However the traffic signals at this junction and at the Brampton Road / Hinchingbrooke Park Road junction could be used to regulate flows entering the town centre thus ensuring that the town centre junctions would not get overloaded.

Brampton Road / Underpass Junction It is understood that changes have been made to the signal timings at the Brampton Road / Edison Bell Way junction in response to complaints about the level of queuing that occurs in the peak periods on the Station access. Updated traffic signal data has been obtained from Cambridgeshire County Council, which has been incorporated in to the ‘Do-Minimum’ operational assessments as part of the work undertaken to update the operational assessments based on the CHARM3a traffic forecasts. The results of the ‘Do-Minimum’ (without scheme) operational assessment undertaken for the Brampton Road / underpass junction are summarised in Table A.27. Table A.27: Brampton Road / Underpass Junction Capacity Assessment (‘Do-Minimum’ scenario)

Junction Arm






RFC (%)

Queue (vehs)

RFC (%)

Queue (vehs)

RFC (%)

Queue (vehs)

RFC (%)

Queue (vehs)

Underpass 35% 0 71% 4 39% 0 76% 5

Brampton Road (east)

41% 0 40% 0 45% 0 45% 0

Brampton Road (west)

41% 0 39% 0 47% 0 41% 0

The operational assessment indicates that all arms of the Brampton Road / underpass junction are forecast to operate within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035. It is expected that slow moving queues of traffic on Brampton Road from the junction with Edison Bell Way would extend past this junction in the peak hours. This would result in worse performance than the operational assessment suggests.


In light of the recent changes made to the traffic signal timings at the Brampton Road / Edison Bell Way junction, the cycle time at this junction in the ‘Do-Something’ scenario has been increased to 120 seconds in both the ‘traffic optimised’ and ‘NMU optimised’ scenarios for consistency with the existing situation. Since both the ‘traffic optimised’ and ‘NMU optimised’ scenarios have the same staging and cycle time, there is no difference between them and therefore only a single ‘Do-Something’ scenario has been assessed. The results of the ‘Do-Something’ (with scheme) operational assessment undertaken for the Brampton Road / Underpass junction are summarised in Table A.28. Table A.28: Brampton Road / Underpass Junction Capacity Assessment (‘Do-Something’ scenario)

Junction Arm






RFC (%)

Queue (vehs)

RFC (%)

Queue (vehs)

RFC (%)

Queue (vehs)

RFC (%)

Queue (vehs)

Underpass 36% 2 34% 5 25% 2 33% 4


46% 0 46% 0 47% 3 45% 2


40% 0 46% 1 41% 1 44% 1

The operational assessment indicates that all arms of the Brampton Road / Underpass junction are forecast to operate within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035. Again, it is expected that slow moving queues of traffic on Brampton Road from the junction with Edison Bell Way would extend past this junction in the peak hours, resulting in worse performance than the operational assessment suggests.

Brampton Road / Hinchingbrooke Road Junction The results of the ‘Do-Minimum’ (without scheme) operational assessment undertaken for the Brampton Road / Hinchingbrooke Road junction are summarised in Table A.29.


Table A.29: Brampton Road / Hinchingbrooke Road Junction Capacity Assessment (‘Do-Minimum’ scenario)

Junction Arm






RFC (%)

Queue (vehs)

RFC (%)

Queue (vehs)

RFC (%)

Queue (vehs)

RFC (%)

Queue (vehs)

Hinchingbrooke Road

29% 0 52% 1 38% 0 74% 5


37% 0 37% 0 41% 0 41% 0

Hinchingbrooke Road

28% 0 32% 0 30% 0 33% 0

The operational assessment indicates that all arms of the Brampton Road / Hinchingbrooke Road junction are forecast to operate within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035. It is expected that slow moving queues of traffic on Brampton Road from the junction with Edison Bell Way would extend past this junction in the peak hours. This would result in worse performance than the operational assessment suggests. The results of the ‘Do-Something’ (with scheme) operational assessment undertaken for the Brampton Road / Hinchingbrooke junction are summarised in Table A.30. Table A.30: Brampton Road / Hinchingbrooke Road junction capacity assessment (‘Do-Something’ scenario)

Junction Arm






DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

Hinchingbrooke Road

56% 11 57% 13 53% 12 56% 13


54% 9 55% 12 63% 15 57% 15

Hinchingbrooke Road

20% 7 24% 9 23% 9 23% 9

Cycle Time (secs)

120

The operational assessment indicates that all arms of the Brampton Road / Hinchingbrooke Road junction are forecast to operate within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035.


Again, it is expected that slow moving queues of traffic on Brampton Road from the junction with Edison Bell Way would extend past this junction in the peak hours, resulting in worse performance than the operational assessment suggests. However the traffic signals at this junction and at the Hinchingbrooke Park Road / Views Common Link junction could be used to regulate flows entering the town centre thus ensuring that the town centre junctions would not get overloaded. Brampton Road / Edison Bell Way Junction The results of the ‘Do-Minimum’ (without scheme) operational assessment undertaken for the Brampton Road / Edison Bell Way junction are summarised in Table A.31. Table A.31: Brampton Road / Edison Bell Way Junction Capacity Assessment (‘Do-Minimum’ scenario)

Junction Arm






DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)


55% 11 78% 23 65% 15 90% 33

Edison Bell Way 64% 5 73% 6 69% 7 80% 11


68% 17 75% 18 76% 20 86% 22

Station Access 7% 0 9% 1 10% 0 10% 1

Cycle Time (secs)

120

The operational assessment indicates that all arms apart from Brampton Road (west) and Brampton Road (east) are forecast to operate within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in 2020, but the junction would be operating close to capacity in the PM peak hour by 2035. In practice, there are a number of other factors which affect the performance of this junction, including its use by emergency vehicles accessing the nearby hospital, police and fire stations; buses blocking through traffic on the approaches; congestion associated with school pick-up and drop-off; and pedestrians crossing the road away from designated crossing points. In combination, these effects would be expected to worsen the performance of the junction and would result in additional delays at the junction over and above those forecast in the operational assessments. However, due to the limitations of the modelling software, these effects cannot be replicated in the results of the operational assessments.


The results of the ‘Do-Something’ (with scheme) operational assessment undertaken for the Brampton Road / Edison Bell Way junction are summarised in Table A.32. Table A.32: Brampton Road / Edison Bell Way Junction Capacity Assessment (‘Do-Something’ scenario)

Junction Arm






DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)


77% 30 94% 54 93% 50 99% 63

Edison Bell Way 85% 14 99% 29 98% 27 102% 36


54% 3 37% 2 57% 3 46% 3

Mill Common Link

64% 8 64% 8 63% 9 61% 9

Cycle Time (secs)

120

The operational assessment indicates that, the Brampton Road / Edison Bell Way junction is forecast to operate at capacity in both 2020 and 2035. For the reasons described above, the actual performance of the junction is expected to be worse than the operational assessments suggest, leading to longer queues and more delay in all scenarios. However, these effects cannot be replicated in the operational assessments due to the limitations of the modelling software. Ermine Street / Edison Bell Way Junction The results of the ‘Do-Minimum’ (without scheme) operational assessment undertaken for the Ermine Street / Edison Bell Way junction are summarised in Table A.33. Table A.33: Ermine Street / Edison Bell Way Junction Capacity Assessment (‘Do-Minimum’ scenario)

Junction Arm






DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

Ermine Street (west)

42% 8 47% 10 56% 13 53% 12

Ermine Street (east)

54% 5 58% 5 62% 7 66% 9

Edison Bell Way 16% 3 17% 3 20% 4 26% 5


Cycle Time (secs)

120

The operational assessment indicates that all arms of the Ermine Street / Edison Bell Way junction are forecast to operate within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035. This junction is also expected to be affected by slow moving traffic blocking back from the Brampton Road / Edison Bell Way junction, resulting in worse performance than the operational assessments suggest. The results of the ‘Do-Something’ (with scheme) operational assessment undertaken for the Ermine Street / Edison Bell Way junction are summarised in Table A.34. Table A.34: Ermine Street / Edison Bell Way Junction Capacity Assessment (‘Do-Something’ scenario)

Junction Arm






DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

Ermine Street (west)

52% 12 62% 16 65% 17 64% 16

Ermine Street (east)

66% 9 69% 8 71% 10 71% 11

Edison Bell Way 28% 6 25% 5 31% 7 29% 6

Cycle Time (secs)

120

The operational assessment indicates that, all arms of the Ermine Street / Edison Bell Way junction are forecast to operate within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035. Again, the performance of the junction is expected to be adversely affected by slow moving traffic blocking back from the Brampton Road / Edison Bell Way junction, resulting in worse performance than the operational assessments suggest. Mill Common Link / Pathfinder Link Junction The Mill Common Link / Pathfinder Link junction is a new signalised junction and therefore no ‘Do-Minimum’ (without scheme) operational assessment has been undertaken. The results of the ‘Do-Something’ (without scheme) operational assessment undertaken for the Mill Common Link / Pathfinder Link Junction are summarised in Table A.35.


Table A.35: Mill Common Link / Pathfinder Link Junction Capacity Assessment (‘Do-Something’ scenario)

Junction Arm






DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

Mill Common Link (west)

51% 5 59% 6 64% 8 62% 7

Pathfinder Link 67% 13 71% 13 73% 16 72% 14

Mill Common Link (east)

50% 12 51% 12 52% 13 50% 12

Cycle Time (secs)

90

The operational assessment indicates that, all arms of the Ermine Street / Edison Bell Way junction are forecast to operate within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035. Pathfinder Link / Ring Road junction The Pathfinder Link / Ring Road junction is a new (signalised) junction and therefore no ‘Do-Minimum’ (without scheme) operational assessment has been undertaken. The results of the ‘Do-Something’ (with scheme) operational assessment undertaken for the Pathfinder Link / Ring Road junction are summarised in Table A.36. Table A.36: Mill Common Link / Pathfinder Link Junction Capacity Assessment (‘Do-Something’ scenario)

Junction Arm






DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

Prince’s Street 12% 1 31% 2 20% 1 71% 5

Castle Moat Road

74% 17 62% 14 87% 24 68% 17

Pathfinder Link 74% 13 62% 8 85% 19 58% 7

Cycle Time (secs)

90

The operational assessment indicates that, all arms apart from the Castle Moat Road in the 2035 AM peak are forecast to operate within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035.


North-West Cambridge Junction

The results of the ‘Do-Minimum’ (without scheme) operational assessment undertaken for the North-West Cambridge junction are summarised in Table A.37.

Table A.37: North-West Cambridge Junction Capacity Assessment (‘Do-Something’ scenario)

Junction Arm






DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

Huntingdon Road (east)

32% 3 58% 7 56% 6 61% 7

Site Access 14% 1 9% 1 28% 2 35% 2


36% 5 28% 3 41% 5 30% 3

Cycle Time (secs)

90

The operational assessment indicates that all arms of the North-West Cambridge junction are forecast to operate within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour) in both 2020 and 2035. The operation of this junction is expected to be affected by slow moving traffic on Huntingdon Road, resulting in worse performance than the operational assessments suggest. However, due to the limitations of the modelling software, these effects cannot be replicated in the results of the operational assessments. The results of the ‘Do-Something’ (with scheme) operational assessment undertaken for the North-West Cambridge junction are summarised in Table A.38. Table A.38: North-West Cambridge Junction Capacity Assessment (‘Do-Something’ scenario)

Junction Arm






DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

DoS (%)

Queue (pcus)

Huntingdon Road (east)

27% 3 46% 5 53% 6 59% 7


Site Access 16% 1 10% 1 38% 3 45% 3


55% 9 42% 6 65% 12 77% 17

Cycle Time (secs)

90

The operational assessment indicates that all arms of the North-West Cambridge junction are forecast to operate within capacity (RFC less than or equal to 85%) in both time periods (AM peak hour and PM peak hour). The operation of this junction is expected to be affected by slow moving traffic on Huntingdon Road, resulting in worse performance than the operational assessments suggest.


Appendix B


Bar Hill / Local Access Road Junction The results presented in Appendix A indicate that in 2035 the Bar Hill / Local Access Road junction is forecast to operate in excess of design capacity in the AM peak hour. Therefore, a sensitivity test has been undertaken in which the Link Road to the northern junction is marked with one left and two right turn lanes (as opposed to two left and one right turn lane in the DCO scheme). The results of the sensitivity test are summarised in Table B.1. Table B.1: 2035 DS+ Junction Capacity Assessments, Bar Hill/Local Access Road Junction Alternative Layout

Junction Link/Arm

AM Peak PM Peak

DCO Layout Alt. Layout DCO Layout Alt. Layout

DoS Queue DoS Queue DoS Queue DoS Queue

(%) (Vehs) (%) (Vehs) (%) (Vehs) (%) (Vehs)

Northern Junction

Hatton’s Road (N)

84% 48 77% 38 66% 23 66% 23

Link Road

90% 12 72% 10 80% 12 77% 8

Hatton’s Road (S)

65% 13 59% 10 70% 31 58% 19

Southern Junction

Link Road

82% 14 82% 14 84% 12 84% 12

LAR (E) 83% 12 83% 12 84% 13 84% 13

LAR (W) 33% 4 31% 4 54% 7 54% 7

The operational assessments undertaken for the Alternative Layout indicate that the improvements are likely to result in the Link Road to the northern junction operating significantly better than in the original model with the DCO layout, with a maximum DoS of 77% in the PM peak hour. It is therefore proposed that the detailed design of the scheme would be based on this alternative layout. Histon Alternative Layout The results presented in Appendix A indicate that in 2035 the Histon junction is forecast to operate in excess of capacity in both the AM and PM peak hours. Accordingly, investigations have been made to make small changes to the junction layout to improve this situation. A sensitivity test has been undertaken in which the northern circulatory carriageway is widened from two to three lanes, with one lane serving the A14 eastbound and two lanes for circulating traffic. The results of the sensitivity test are summarised in Table B.2.


Table B.2: 2035 DS+ Junction Capacity Assessments, Histon Interchange, Alternative Layout

Arm Lane

AM Peak PM Peak

DCO Layout Alt. Layout DCO Layout Alt. Layout

DoS Queue DoS Queue DoS Queue DoS Queue

(%) (pcus) (%) (pcus) (%) (pcus) (%) (pcus)

A14 EB

Off-Slip

Entry 85% 40 85% 44 79% 27 90% 34

Circ. 61% 36 61% 27 65% 27 70% 28

B1049 Entry 89% 42 63% 27 60% 18 54% 17

Circ. 72% 32 59% 32 67% 34 46% 28

A14 WB

Off-Slip

Entry 83% 23 83% 29 62% 24 62% 24

Circ. 83% 31 83% 30 70% 33 70% 25

Cambridge Road

Entry 132% 316 132% 42 131% 362 131% 362

Circ. 27% 7 27% 14 46% 20 46% 20

The operational assessments undertaken for the Alternative Layout indicate that the improvements are likely to significantly improve the performance of the B1049 approach in both the AM and PM peak hours. The junction is forecast to continue to operate in excess of capacity on the Cambridge Road approach in both the AM and PM peak hours. There is forecast to be a minimal change in average peak hour delay across the junction as a result of the improvement. The Alternative Layout is forecast to achieve ‘nil detriment’ in both the AM and PM peak hours. It is therefore proposed that the detailed design would be based on this alternative.


Appendix C


The operational assessments undertaken for the Do-Something scenario in Appendix A are based on the 2020 and 2035 DS+ (Core) scenario. This assumes 2,315 homes at Northstowe in 2020, increasing to 5,031 homes by 2035. The Northstowe Area Action Plan ultimately includes plans for up to 10,000 homes. Planning approval has not yet been granted for these additional homes and therefore they are not included as part of the ‘core’ scenario. Nonetheless, Highways England has committed to safeguard land and provide earthworks and structures at Bar Hill that are capable of accommodating the full build out of Northstowe, providing a scheme such that only relatively modest alterations would be required to be implemented by the developer to accommodate the full build out and hence limit disruption to the travelling public Other junctions in the vicinity of the Northstowe development have also been assessed to determine whether the proposed designs are capable of accommodating the additional traffic generated by the development. In order to ensure that the junction designs are robust, a series of operational assessments have been undertaken for the 2035 DS++ (high development) scenario. The following junctions in the vicinity of the development have been assessed:

• Swavesey North roundabout;

• Swavesey South roundabout;

• Swavesey Services roundabout;

• Swavesey Anderson Road roundabout;

• Lolworth junction;

• Bar Hill Main roundabout;

• Bar Hill South roundabout;

• Bar Hill/Local Access Road junction;

• Dry Drayton North roundabout;

• Dry Drayton South roundabout;

• Girton Interchange West roundabout; and

• Girton Interchange East roundabout.


Swavesey Junction The 2035 DS++ traffic flows have been input into the junction models prepared for the Swavesey (North), Swavesey (South), Swavesey Services and Anderson Road roundabouts, with Table C.1 summarising the results of the assessments undertaken for the AM and PM peak hours. Table C.1: 2035 DS++ Junction Capacity Assessments, Swavesey

Arm

AM Peak PM Peak

RFC Queue Total Delay


(%) (Vehs) (pcuHr) (%) (Vehs) (pcuHr)

Swavesey North Roundabout

A Bucking Way Rd 88% 6 3.6 96% 15 7.2

B A14 EB Slips 22% 0 0.3 31% 0 0.5

C Bridge 57% 1 1.3 51% 1 1.1

D Local Access Road 84% 5 3.9 78% 4 3.0

Swavesey South Roundabout

A Bridge Link 27% 0 0.4 43% 1 0.9

B A14 Off-Slip 73% 3 2.4 76% 3 2.8

C New Link Road 71% 2 1.9 60% 2 1.3

D Local Access Road 0% 0 0.0 0% 0 0.0

E A14 West On-Slip Exit Arm Exit Arm

Swavesey Services Roundabout

A New Link Road (W) 39% 1 0.7 59% 1 1.5

B A14 Off-Slip (E) 0% 0 0.0 0% 0 0.0

C Cambridge Services 26% 0 0.4 28% 0 0.5

D High Street (Boxworth)

29% 0 0.5 17% 0 0.2

Swavesey Anderson Road Roundabout

A Bucking Way Road (N)

49% 1 1.1 58% 1 1.4

B Anderson Road 2% 0 0.0 5% 0 0.1

C Bucking Way Road (S)

17% 0 0.2 40% 1 0.7

D Link Road 39% 1 0.7 56% 1 1.4

The 2035 DS++ operational assessments undertaken for the Swavesey junctions indicate that they are all forecast to operate within capacity in both the AM and PM peak hours, albeit that Bucking Way Road (N) approach to the Swavesey (N) junction is forecast to be approaching capacity.


Lolworth Junction

The 2035 DS++ traffic flows have been input into the junction model prepared for the Lolworth junction, with Table C.2 summarising the results of the assessments undertaken for the AM and PM peak hours. Table C.2: 2035 DS++ Junction Capacity Assessments, Lolworth Junction

Movement

AM Peak PM Peak




Robin’s Lane B-C Left 1% 0 0.0 1% 0 0.0

B-A Right 0% 0 0.0 0% 0 0.0

Local Access Rd (E)

C-AB Ahead & Right

1% 0 0.0 1% 0 0.0

The 2035 DS++ operational assessments indicate that it is forecast to operate well within capacity in both the AM and PM peak hours. Bar Hill Junction The 2035 DS++ traffic flows have been input into the junction models prepared for the main Bar Hill roundabout, Bar Hill South roundabout and Bar Hill/Local Access Road junction, with Table C.3 summarising the results of the assessments undertaken for the AM and PM peak hours. Table C.3: 2035 DS++ Junction Capacity Assessments, Bar Hill

Model Ref/Arm

AM Peak PM Peak




Bar Hill Main Roundabout

A A14 (W) Slips 61% 2 1.3 78% 3 2.2

B Hatton's Road 35% 1 0.6 16% 0 0.2

C A14 (E) Slips 64% 2 1.5 61% 2 1.5

D B1050 (S) 52% 1 1.0 74% 3 2.3

Bar Hill South Roundabout

A Hatton's Road (B1050) 47% 1 1.0 46% 1 0.9

B Golf Course 7% 0 0.1 5% 0 0.1

C Crafts Way 34% 1 0.5 18% 0 0.2

D Saxon Way 39% 1 0.7 82% 4 3.6



J1:7 Hatton’s Road (N)

Northern Junction

78% 41 10.4 66% 25 8.2

J1:8 Link Road 27% 4 2.2 74% 9 3.5

J1:10 Hatton’s Road (S)

46% 11 2.8 70% 32 7.7

J1:2 Link Road Southern Junction

50% 3 1.6 57% 5 2.8

J1:4 LAR (E) 27% 2 0.9 42% 3 1.6

J1:6 LAR (W) 20% 3 0.8 39% 6 1.8

The 2035 DS++ operational assessments undertaken for the Bar Hill junctions indicate that they are all forecast to operate within capacity in both the AM and PM peak hours. Dry Drayton Junction The 2035 DS++ traffic flows have been input into the junction models prepared for the Dry Drayton North and Dry Drayton South roundabouts, with Table C.4 summarising the results of the assessments undertaken for the AM and PM peak hours. Table C.4: 2035 DS++ Junction Capacity Assessments, Dry Drayton

Arm

AM Peak PM Peak




Dry Drayton North Roundabout

A Local Access Road (W) 28% 0 0.4 32% 1 0.5

B Dry Drayton Road (N) 66% 2 1.9 50% 1 1.1

C Oakington Road 64% 2 1.7 68% 2 2.0

Dry Drayton South Roundabout

A Oakington Road (W) 62% 2 1.6 61% 2 1.5

B Oakington Road (E) 68% 2 2.0 51% 1 1.1

C Local Access Road 31% 0 0.5 54% 1 1.2

The 2035 DS++ operational assessments undertaken for the Dry Drayton North and Dry Drayton South roundabouts indicate that both junctions are forecast to operate well within capacity in both the AM and PM peak hours. Girton Interchange The 2035 DS++ traffic flows have been input into the junction models prepared for the Girton Interchange West and East roundabouts, with Table C.5 summarising the results of the assessments undertaken for the AM and PM peak hours.


Table C.5: 2035 DS++ Junction Capacity Assessments, Girton Interchange

Arm

AM Peak PM Peak




Girton Interchange (W) Roundabout

A A14 On-Slip Exit Arm Exit Arm

B Local Access Road (E) 55% 1 1.3 58% 1 1.4

C Local Access Road (W) 55% 1 1.2 55% 1 1.2

Girton Interchange (E) Roundabout

A A14 Off-Slip 70% 2 2.1 89% 7 5.0

B Local Access Road (E) 74% 3 2.6 81% 4 3.5

C Local Access Road (W) 29% 0 0.5 24% 0 0.4

The 2035 DS++ operational assessments undertaken for the Girton Interchange West and East roundabouts indicate that both junctions are forecast to operate within capacity in both the AM and PM peak hours.


Appendix D

!!!!!!!!!!!!!!

!!!!!

!!!

!!!

!!!!

!!!!

!!!!!!!!!!!! !!!!!!!!!!

!!!! !!!!!!!

!!! !!!!!!!!!!!!!!!

!!!!!!!! !!

!!!

!!!!

!

! !!!!!!

!!

!!!

!

!

!

!

!

!!

!!!!

!!!!!!!!!!!!!!!!!!!

!! !!!!!!!!!!!!

!!!

!!!

!

!

!

!!!!!!

!

!

!!

!!!!

!!!!!! !!!!!!!!!

!!!!!!! !! !!!

!

!!

!

!!!!!!!!!!!!!!

!!!!

!

!

!

!

! !

!!!!

!

!!

!

! !

!!!! !!!!!!!

!!!!!!!!! !!!!!!

!!!

!!!!!!

!!!!

!

!!

!!

!

!!

! !! ! !!!!!! ! ! !!!! ! ! !!

!!!!!

!!!!

!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!

!

!!! !!!!

!!!

!

!!!!!!!!!

!!!!

!!!!

!!!

!!!!

!!!

!!

!

!!

!!

!!

!!

!!! !!!!!!

!!!!!!!!!!!

!!!!!

!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!

!!!!!!!!!! !!!

!!!!!!!!!!!!!!!

!

!!

!

!

!

!!!

!

!

!!!

!!

!!!

!

!

!!!!!

!

!

!!

!!!

!

!!!

!

!!!

!

!

!

!

!

!!!!!!!!

© Crown copyright and database rights 2013 Ordnance Survey 100030649. This drawing is not to be used in whole in or part other than for the intended purposeand project as defined on this drawing. Refer to the contract for full terms and conditions.

A14 CAMBRIDGE TO HUNTINGDONIMPROVEMENT SCHEME

Drawing Title

Project

Drawing Status

Drawing No.Client No.

FOR INFORMATIONScale @A3Jacobs No.

DO NOT SCALEB2410000

Drawn Check'd Appr'dPurpose of revisionRev. DateEW XX XXInitial Issue0 APR15

1:100,000

XXRev'd

Client

/

(Approx.)

LegendCHARM3A Modelled changes in NO2 (µg/m3) - 2020Difference! > -2! -2 - 0! 0 - 0.4! 0.4 - 2! > 2

DCO boundary

B2410000/INFO/AQ/02

Air quality - Predicted magnitude of changeof pollutant concentrations

0 4.5 9 13.5 18 22.52.25Kilometres

!!!!!!!!!!!!!!!

!!!!!

!!!

!!!

!!!!

!!!!

!!!!!!!!!!!! !!!!!!!!!!

!!!! !!!

!!!!!!!! !!!

!!!!!!!!!!!!

!!!!!!!! !!

!!!

!!!!

!

! !!!!!!

!!

!!!

!

!

!

!

!

!!

!!!!

!!!!!!!!!!!!!!!!!!!!

!! !!!!!!!!!!!!

!!!

!!!

!

!

!

!!!!!!

!

!

!!

!!!!

!!!!!! !!!!!!!!!

!!!!!!! !! !!!

!

!!!

!

!!!!!!!!!!!!!!

!!!!

!

!

!

!

! !!

!!!!

!

!!

!

! !

!!!! !!!!!!

!!!!!!!!! !!!!!!

!!!

!!!!!!

!!!!

!

!!

!!

!

!!

! !! ! !!!!!! ! ! !!!! ! ! !!

!!!!!

!!!!

!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!

!

!!! !!!!

!!!

!

!!!!!!!!!

!!!!

!!!!

!!!

!!!!

!!!

!!

!

!!

!!

!!

!!

!!! !!!!!!

!!!!!!!!!!!

!!!!!

!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!

!!!!!!!!!! !!!

!!!!!!!!!!!!!!!

!

!!

!

!

!

!!!

!

!

!!!

!!

!!!

!

!

!!!!!

!

!

!!

!!!

!

!!!

!

!!!

!

!

!

!

!

!!!!!!!!

© Crown copyright and database rights 2013 Ordnance Survey 100030649. This drawing is not to be used in whole in or part other than for the intended purposeand project as defined on this drawing. Refer to the contract for full terms and conditions.

A14 CAMBRIDGE TO HUNTINGDONIMPROVEMENT SCHEME

Drawing Title

Project

Drawing Status

Drawing No.Client No.

FOR INFORMATIONScale @A3Jacobs No.

DO NOT SCALEB2410000

Drawn Check'd Appr'dPurpose of revisionRev. DateEW XX XXInitial Issue0 APR15

1:100,000

XXRev'd

Client

/

(Approx.)

LegendCHARM3A Modelled changes in PM10 (µg/m3) - 2020Difference! > -0.4! -0.4 - 0! 0 - 0.4! 0.4 - 2

DCO boundary

B2410000/INFO/AQ/04

Air quality - Predicted magnitude of changeof pollutant concentrations

0 4.5 9 13.5 18 22.52.25Kilometres

Documents

A Traffic Modelling Update Report - Abode Group