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Transport and Strategic Regeneration Welsh Assembly Government M4 Corridor Enhancement

Measures Strategy, Appraisal and Monitoring

May 2010

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Transport and Strategic Regeneration �Welsh Assembly Government M4 Corridor Enhancement MeasuresStrategy, Appraisal and Monitoring


Ove Arup & Partners Ltd Draft 2 4 May 2010

Contents

Page

1 INTRODUCTION 1

1.1 Background 1

1.2 Purpose of this Report 1

1.3 The Problem 2

1.4 The Need for a Strategy 2

2 STRATEGY DEVELOPMENT 3

2.1 Making Best Use of Existing Capacity 3

2.2 Improving the Resilience of the Network 3

2.3 Improving Public Transport 3

2.4 Conceptual Strategy 4

3 SCHEME APPRAISAL 7

3.1 Strategic Performance Indicators 8

3.2 Scheme Specific Objectives 11

4 IMPLEMENTATION AND MONITORING 17

5 SUMMARY 18

Appendices

Appendix A

Transport Planning Objectives

Appendix B

Problems with the Transport System in South East Wales

Appendix C

Results of Capacity Assessments of Existing M4 (J25a - J29)

4



Page 1 Ove Arup & Partners LtdDraft 2 4 May 2010

1 INTRODUCTION

1.1 Background

In December 2004, the Minister for Economic Development and Transport reported on the

outcome of his review of transport programmes, which he had undertaken to ensure a good

strategic fit with ‘Wales: A Better Country’ and the ‘Wales Spatial Plan’. One of the

conclusions of the review was that additional capacity was required on the M4 motorway in

south east Wales, in order to reduce congestion, improve resilience and remove an obstacle

to greater prosperity along the whole corridor through to Swansea and West Wales.

In addition to widening the motorway north of Cardiff, the Minister announced proposals to

develop a New M4 south of Newport between Magor and Castleton. At the same time, it

was announced that the existing route could include priority measures for public transport

and multiple occupancy vehicles. This resulted in investigations being undertaken as part of

the New M4 Project.

A WelTAG Stage 1 appraisal1 was undertaken as part of the New M4 Project. This has

shown that an option of corridor enhancement measures (CEMs) would make a contribution

to most of the transport planning objectives (TPOs) that had been drawn up at the WelTAG

Planning Stage. The TPOs are included for reference at Appendix A.

The National Transport Plan (NTP), which was published following consultation in March

2010, sets out the detail of how the Welsh Assembly Government will deliver the Wales

Transport Strategy ‘One Wales: Connecting the Nation’ over the next five years. This Plan

recognises that “for a long time there have been concerns about the section of motorway

around Newport, which falls well short of modern design standards. These centre on peak-

time capacity, safety and the resilience of the local network”. As part of the NTP, the

Assembly will:

“Deliver a package of measures designed to improve the efficiency of the M4 in south-east

Wales, including public transport enhancements, making the best possible use of the

motorway and improving the resilience of the network.”

In order to achieve the above, Arup was asked to investigate potential schemes to improve

the operation of the existing M4 around Newport, as part of the New M4 Project. Such

schemes are to be implemented as interim measures to:

• make best use of existing infrastructure and capacity;

• improve the resilience of the network; and

• improve public transport.

A strategy was thus required to embrace the above three themes and to ensure that any

measures put forward would contribute effectively to one or more of these themes.

1.2 Purpose of this Report

The purpose of this report is to outline the process of strategy development and the

conceptual strategy that has emerged from this process. It also describes how options for

individual measures/schemes are to be appraised by drawing up a set of Strategic

Performance Indicators as well as Scheme Specific Objectives. This report also outlines a

suggested methodology for monitoring progress with individual measures as well as post

implementation effectiveness.

1 New M4 Project, Magor to Castleton, WelTAG Appraisal Report Stage 1, Arup, January 2010

5




1.3 The Problem

The M4 motorway in south east Wales is running close to capacity with traffic volumes

continuing to grow, causing increasing congestion. The motorway around Newport is

congested during weekday peak periods, resulting in slow journey times and stop start

conditions, with frequent incidents and accidents causing delay. The motorway does not

conform to current standards and has closely spaced junctions with sub-standard slip road

visibility. Heavy congestion occurs along the two lane stretch either side of the Brynglas

Tunnels. As traffic volumes increase over time, the situation will worsen, accidents and

incidents are likely to increase with journey times becoming increasingly unreliable,

hindering economic growth.

Recent improvement measures include widening the M4 from dual 2 lanes to dual 3 lanes

between Castleton (Junction 29) and Coryton (Junction 32) as well as ‘making better use’

work to improve traffic flow on the motorway. However, additional measures are required in

order to address safety and capacity issues on the motorway and the resilience of the

strategic road network around Newport.

A WelTAG Planning Stage Workshop in October 2007 identified the transport problems.

These are listed for reference at Appendix B.

1.4 The Need for a Strategy

There is a need to safeguard the capacity of the motorway for use by longer distance traffic

and especially freight vehicles. Local trips should be discouraged from using the motorway

around Newport. Improved access to the Newport Southern Distributor Road from the

motorway could provide an attractive expressway to those areas of Newport that lie to the

south of the motorway.

There is also a need to improve the resilience of the main road network around Newport.

This means making the network more capable of coping with events, incidents, accidents

and maintenance works as well as high traffic demand.

Improvement to public transport would increase travel choice.

6




2 STRATEGY DEVELOPMENT

The adoption of a strategy for the M4 transport corridor through south east Wales that would

make better use of existing infrastructure and services would be likely to result in efficiency

gains. In particular, the aim is to improve operating conditions on the motorway around

Newport. A central plank of this strategy, therefore, will be to safeguard the capacity of the

motorway for use by longer distance/strategic traffic and especially freight vehicles. This

might involve closure of those junctions that link non-strategic routes to the motorway.

Conversely, those junctions that link strategic routes to the motorway may benefit from

improvement.

The following three themes have been adopted as a basis for the overall strategy:

• Making the best possible use of the existing capacity;

• Improving the resilience of the network; and

• Improving public transport.

2.1 Making Best Use of Existing Capacity

The Southern Distributor Road (SDR), which skirts the built-up area of Newport to the south,

distributes local traffic. It has frequent junctions along its length which, being roundabouts,

tend to disrupt through movements. As a consequence, the SDR is currently seldom the

route of choice for other than those drivers who have destinations immediately off it. When

there are significant delays on the motorway around Newport, the SDR currently provides

an alternative route, albeit of limited attractiveness.

If capacity on the motorway around Newport is to be safeguarded for through movements,

traffic accessing Newport needs to be encouraged to use the SDR. To achieve this,

consideration may need to be given to any sources of traffic delay along the route of the

SDR. These are likely to include Tredegar Park interchange (J28) and the Pont Ebbw

roundabout. Further consideration may also be given to the potential extension of the SDR

to the east (by upgrade to the Steelworks Access Road – Magor to Queensway Meadows).

The aim would be to create an expressway route into Newport from both east and west with

access from the south of the city.

2.2 Improving the Resilience of the Network

Within the existing motorway landtake around Newport, there may be scope to undertake

incremental widening and modification to existing junctions to maximise the roadspace

available to through traffic on the motorway. Consideration should also be given to the

development of an incident/event management plan that would maximise the capacity

available on alternative east/west routes temporarily should the need arise. This may

influence the form of junctions to be provided along the upgraded Steelworks Access Road

and SDR.

2.3 Improving Public Transport

During peak travel periods, there is a predominance of car driver commuters, often resulting

in single occupancy car use. Therefore, any measures that increase vehicle occupancy

would be likely to impact positively on operating conditions on the motorway during peak

periods. Increase in travel choice is necessary to create the potential for modal shift and

reduced dependence on driving a car for the complete journey. The provision of Park and

Share and Park and Ride facilities in strategic locations that give car drivers genuine choice

may impact positively. However, there is unlikely to be a sea change in travel behaviour in

the Newport area in the short to medium term. Thus, whilst investment in public transport

would be beneficial in increasing travel choice and accessibility, it is unlikely to have a

significant impact on congestion on the M4, at least in the short to medium term.

7




2.4 Conceptual Strategy

The premise upon which the current corridor enhancement strategy has been based is that

available capacity on the motorway around Newport is to be safeguarded for longer distance

and strategic movements of people and goods. Furthermore, where it is practical and

politically, socially, environmentally and economically acceptable, the transport capacity of

the east/west corridor around Newport should be increased.

The physical constraints imposed by the River Usk Viaduct and the Brynglas Tunnels on the

section of motorway between Junctions 25a and 26 make on-line widening of this section of

the motorway impractical. Therefore, it has to be accepted that this section of the motorway

has a finite capacity, which must be seen as a vulnerable link in the strategic road network.

Whilst additional capacity could be achieved on other sections of the motorway around

Newport, the value of such measures must be weighed against the restriction in capacity on

the Junction 25a – 26 link. The concept must, therefore, be to manage/regulate demand for

use of the Junction 25a – 26 link, at least, as an interim solution. This might be achieved by

restricting access locally to the motorway, by providing acceptable alternative routes and by

the introduction of Managed Motorway principles including variable speed limits.

Previous work undertaken by Arup2 has highlighted that there are a number of measures

that have the potential to improve the efficiency of operation of the M4 transport corridor

through south east Wales. Many of the measures identified would complement each other,

whilst others may be classed as discrete initiatives.

Intelligent Transport Systems (ITS) may be called upon to support day to day management

of traffic movements on the motorway and the strategic transport networks and also to

assist with incident and event management.

Measures to increase driver choice aimed at encouraging mode shift away from private

vehicle motorway travel may also be deployed. These might include improvement to public

transport and provision of Park and Ride facilities.

The previous work has shown that there is scope to achieve incremental improvements to

operating conditions within the M4 transport corridor and the measures that have hitherto

been considered are aimed at efficiency improvements within the corridor. However, since

the available capacity on the motorway around Newport is limited and, at times, currently

causing restraint, there will be a limit to the relief that may be obtained from corridor

enhancement.

Measures such as the removal of the east facing slip roads at Junction 26 (impact of around

4% reduction in traffic flows through Brynglas Tunnels) and at-grade upgrading of junctions

along the Southern Distributor route (impact of around 3% reduction in motorway traffic

flows across the River Usk) would be likely to result in the greatest reduction in traffic

volumes using the Brynglas Tunnels. This suggests that around 7–8% would be a realistic

initial target for reduction to traffic volumes through Brynglas Tunnels. It is possible that the

introduction of further measures, including junction closures or restriction of access to/from

the motorway at selected junctions around Newport might lead to further reduction in

motorway flows. Conversely, on-line widening / hard shoulder running would encourage

motorway use. Research to date has shown that an upper limit of traffic flow reduction

through Brynglas Tunnels would be reached at around 11% and that an extensive package

of measures would be required to achieve this.3

2 New M4 Project Magor to Castleton, Corridor Efficiency Improvements Report WelTAG Stage 1, Arup, October 2009

3 M4 Corridor Enhancement Measures, Traffic Modelling and Road Network Impacts (Work in Progress), Arup, December 2009

8




Other measures such as the provision of the Steelworks Access Road (SAR) would improve

access to the Newport Eastern Expansion Area. However, during normal operations, in

isolation the SAR is unlikely to impact upon the use of the motorway around Newport.

Nevertheless, when coupled with upgrading of the SDR and modification to Junction 28,

limited reduction in traffic flows on the motorway around Newport may occur, especially

during periods of congestion. During incidents/maintenance works on the motorway, the

SAR, SDR upgrading and J28 improvements would provide increased network resilience.

Traffic forecasting using a SATURN traffic model has indicated that, unless travel behaviour

were to change significantly, even with corridor enhancement measures in place, traffic

congestion and capacity problems could be expected to occur during weekday peak travel

times with increasing frequency some time during the period 2018 to 2024 on the

approaches to Brynglas Tunnels (see Appendix C).

The incremental development of an expressway route into Newport from the south would:

• increase east/west highway capacity;

• strengthen network resilience by offering an alternative traffic route to the motorway;

and

• provide access to new development including housing, employment, retail and park and

ride facilities.

Having regard to the aims stated above, a strategy for corridor enhancement for the

motorway around Newport is illustrated conceptually in Figure 2.1.

9




Figure 2.1: Conceptual Strategy for Corridor Enhancement Measures

10




3 SCHEME APPRAISAL

The Transport Planning Objectives (TPOs) (see Appendix A) developed through the

WelTAG process should form the basis on which any Corridor Enhancement Measures

(CEMs) are initially evaluated. However, to help focus on options that address the problems

on the existing M4 and deliver the intended benefits, a further set of Strategic Performance

Indicators have been developed.

The Strategic Performance Indicators aim to reinforce the proposed Newport Expressway

principle. Namely, the over-arching strategy is to safeguard the capacity of the motorway

around Newport for use by longer distance/strategic traffic and especially freight vehicles.

This may involve closure of those junctions that link non-strategic routes to the motorway.

Conversely, those junctions that link strategic routes to the motorway may need to be

improved. By upgrading the road links around Newport to the south that connect to these

junctions an Expressway will be created to the south of Newport. This will provide an

alternative means of access to the city, which will increase network resilience.

The TPOs and Strategic Performance Indicators should be used in tandem to help arrive at

an effective set of CEMs.

For each CEM, there may be more than one option. In order to choose between options,

Scheme Specific Objectives (SSOs) have been established. The appraisal process thus

comprises of two stages, namely:

• Strategic stage, at which proposed measures are either included or discarded,

depending on how effectively they perform against the TPOs (by appraisal against the

Strategic Performance Indicators). This appraisal may be qualitative or quantitative;

and

• Specific stage, at which schemes/options for individual measures are tested against

objectives set, bearing in mind site specific conditions and opportunities.

This appraisal process is illustrated in Figure 3.1.

Figure 3.1: Appraisal Process for Corridor Enhancement Measures

11




3.1 Strategic Performance Indicators

Consideration of the TPOs and the proposed strategy for corridor enhancement has

enabled a set of Strategic Performance Indicators to be drawn up. The purpose of these

indicators is to identify those TPOs that might be met, in part or whole, by individual CEMs.

This facilitates the appraisal of the relative performance of individual measures and assists

in developing an effective package of measures in order to meet the TPOs.

The Strategic Performance Indicators developed for this purpose are as follows:

1. Encourages use of the SDR by traffic with an Origin or Destination in Newport

2. Improves access/egress between the M4 and Newport Expressway to the west (J28),

east (J23a) and from J24

3. Encourages the use of the M4 between J23a and J29 by through traffic via reduced

journey times and improved reliability

4. Discourages the use of the motorway around Newport for local/short distance trips

5. Minimises adverse environmental impacts

6. Encourages increased vehicle occupancy

7. Improves public transport services/infrastructure

8. Improves driver information and route choice

9. Improves network operating conditions

10. Provides a level of service compatible with demand

11. Increases size of workforce within 30 minute catchment

12. Improves access to development areas (housing etc)

13. Improves access to public services

14. Reduces risk of transport accidents

15. Increases resilience of transport network

16. Improves journey experience of transport users

In addition to the above indicators that may be related to specific TPOs, there is a further

indicator that, whilst not being directly related to any specific TPO, is a fundamental

requirement in order for any measure to go forward. This indicator is that any measure

being considered must meet affordability and deliverability constraints. This could be now

or in the future, so that some measures may need to be delivered during the later stages of

a phased implementation programme. Conversely, some measures may be deemed to

provide “quick wins” with immediate benefits resulting from modest investment and/or

minimal disruption.

The relationship between the Strategic Performance Indicators and the Transport Planning

Objectives is illustrated in Figure 3.2.

The CEMs previously brought forward have been appraised against the Strategic

Performance Indicators. The scoring is based on a -3 to 3 scale where:

3 = large positive 2 = moderate positive

1 = slight positive 0 = neutral -1 = slight negative -2 = moderate negative -3 = large negative

A summary of this strategic stage appraisal is provided in Table 3.1.

12




Figure 3.2: Relationship between Strategic Performance Indicators and TPOs

Strategic Performance Indicators Transport Planning Objectives (see below*)

1 2 3 4 5 6 7 8 9 10 11 12

1. Encourages use of the SDR by traffic with an Origin or Destination in Newport � �

2. Improves access/egress between the M4 and Newport Expressway to the west (J28), east (J23a) and from J24 � � �

3. Encourages the use of the M4 between J23a and J29 by through traffic via reduced journey times and improved reliability

� � �

4. Discourages the use of the motorway around Newport for local/short distance trips �

5. Minimises adverse environmental impacts � � � �

6. Encourages increased vehicle occupancy �

7. Improves public transport services/infrastructure �

8. Improves driver information and route choice �

9. Improves network operating conditions � � � � � �

10. Provides a level of service compatible with demand �

11. Increases size of workforce within 30 minute catchment � � �

12. Improves access to development areas (housing etc) �

13. Improves access to public services �

14. Reduces risk of transport accidents � � �

15. Increases resilience of transport network � �

16. Improves journey experience of transport users �

Meets affordability and deliverability constraints

*Transport Planning Objectives:

TPO1 To improve connectivity within Wales and Internationally along the east-west strategic corridor in South Wales.

TPO5 To increase travel choice for all. TPO9 To improve air quality around Newport.

TPO2 To discourage the use of the motorway around Newport as a local distributor road.

TPO6 To improve accessibility to key centres and services. TPO10 To reduce the number of people subjected to high noise levels.

TPO3 To make better use of the existing highway asset.

TPO7 To improve the transport network management around Newport.

TPO11 To reduce greenhouse gas emissions per vehicle and/or person kilometre.

TPO4 To increase journey time reliability. TPO8 To improve travel safety on the transport network around Newport.

TPO12 To enhance the traveller experience through the gateway to South Wales.

13




Table 3.1: CEM Scores against Strategic Performance Indicators

Measure Unweighted Score

Transport Planning Objectives Impacted Upon

2, 3 1, 3, 7 1, 4, 12

2 9, 10, 11, 12

5 6 7 1, 7, 8, 9, 11, 12

12 3, 5, 6 6 6 4, 8, 12

3, 7 12

Strategic Performance Indicators

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

1. Incremental widening between Junctions 29 and 28 +7 -1 0 2 -1 0 -1 0 0 2 2 1 0 0 1 1 1

2. Hard shoulder running/incremental widening between Junctions 28 and 27

+5 -2 0 2 -2 0 -1 0 0 2 2 1 0 0 1 1 1

3. Incremental widening between Junctions 27 and 26 +5 -2 0 2 -2 0 -1 0 0 2 2 1 0 0 1 1 1

4. Increased length of westbound merge at Junction 29A +9 0 0 0 0 0 0 0 0 3 2 1 0 0 2 0 1

5. At-grade improvement to the A48 Southern Distributor Road (SDR)

+19 3 2 1 0 0 0 0 2 2 2 1 2 1 0 2 1

6. Upgrade to Steelworks Access Road +18 2 2 1 0 0 0 1 2 2 2 1 2 0 0 2 1

7. Improvement to B4245 junction west of Magor +12 1 2 0 1 0 0 0 0 2 2 1 1 0 1 0 1

8. Improvement to Junction 28 with associated works at Bassaleg and Pont Ebbw Roundabouts

+16 1 2 1 1 -1 0 0 0 3 2 2 2 0 1 1 1

9. Closure of Junction 27 +9 0 0 2 2 0 1 1 -1 1 0 1 0 1 2 -1 0

10. Removal of east facing slip roads and widening of west facing slip roads at Junction 26

+12 0 0 1 2 1 2 2 -1 1 1 1 0 1 1 -1 1

11. Removal of east facing slip roads at Junction 25 +6 1 0 1 2 0 1 1 -1 1 0 0 0 0 1 -1 0

12. Lane restriction with enforcement using ITS +6 0 0 1 0 0 0 0 0 1 0 0 0 0 3 1 0

13. Improvement to incident and queue detection using ITS +8 1 1 0 0 0 0 0 2 2 0 0 0 0 1 1 0

14. Traffic monitoring for incident management using ITS +7 0 0 0 0 0 0 0 3 2 0 0 0 0 1 1 0

15. Update to controlled motorway +6 0 0 1 0 1 0 0 0 2 0 0 0 0 1 1 0

16. Improved driver information +8 1 0 0 0 0 0 0 3 1 0 0 0 0 1 1 1

17. Park and Ride at Severn Tunnel Junction +9 0 0 1 0 0 1 2 0 1 0 1 1 0 0 1 1

18. Park and Ride at Magor +4 0 0 0 0 0 1 2 0 1 0 0 0 0 0 0 0

19. Park and Ride at Llanwern +9 1 0 0 0 0 1 2 0 1 0 0 1 1 0 1 1

20. Park and Ride at Rogerstone +8 0 0 0 1 0 1 2 0 1 0 1 0 1 0 0 1

21. Park and Ride at Coedkernew +7 0 0 0 0 -1 1 2 0 1 0 1 1 1 0 0 1

22. Reduction in traffic noise +2 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0

23. East/West Bus Rapid Transit +19 0 0 0 1 1 2 2 0 2 1 2 2 2 0 2 2

24. Re-branding of driver experience on motorway +5 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 3

25. Park and Ride/Parkway railway station at St Mellons +11 0 0 0 0 0 2 2 0 1 1 1 1 1 0 1 1

14




3.2 Scheme Specific Objectives

As a result of the investigations previously carried out, possible measures for further

investigation are summarised in Figure 3.3.

Making the Best

Possible Use of the

Existing Capacity

Improving the Resilience

of the Network

Improving Public

Transport

• Upgrade Steelworks

Access Road (Magor

to Queensway

Meadows)

• At-grade improvements to the

A48 Southern

Distributor Road

(SDR)

• Improvement to Junction 28 (Tredegar

Park)

• Update to Controlled

Motorway between

Junctions 28

(Tredegar Park) and

24 (Coldra)

• Improvement to B4245 junction west of

Magor

• Widening between

Junctions 27 (High

Cross) and 26 (Malpas)

• Widening between

Junctions 29 (Castleton)

and 28 (Tredegar Park)

• Hard shoulder

running/widening

between Junctions 28

(Tredegar Park) and 27

(High Cross)

• Improvements to

A48(M) Junction 29A

(St Mellons)

• Modification to Junction

27 (High Cross)


26 (Malpas)


25 (Caerleon)

• Park & Ride/Share

Option East of Cardiff


Option at Coedkernew


Option at Llanwern

• Park and Ride/Share

Option at Severn

Tunnel Junction

Figure 3.3: Possible Measures for Further Investigation

As a result of the strategic stage appraisal, selected CEMs are currently being developed.

For each measure, broad options are being considered and a scheme or schemes are

emerging. To assist in this process of comparing options and developing schemes, a set of

Scheme Specific Objectives (SSOs) has been drawn up for each measure.

The measures currently being investigated further are as follows:

• modification to Junction 26;

• improvement to Junction 28 with associated works at Bassaleg and Pont Ebbw

roundabouts;

• upgrade to Steelworks Access Road (SAR);

• incremental at-grade improvements to the A48 Southern Distributor Road (SDR);

• improvement to B4245 junction west of Magor;

• improvement to Junction 29A; and

• strategic Park and Ride.

Proposed SSOs for options/schemes for the above measures are outline below.

15




Modification to Junction 26

The presence of east facing slip roads onto and off the motorway at Junction 26 encourages

traffic with an origin or destination in Newport or Cwmbran to use Brynglas Tunnels. There

are alternative routes between Newport and Cwmbran and the motorway. The restriction of

use of the east facing slip roads at Junction 26 to emergency and maintenance vehicles

only would be likely to result in a reduction in traffic passing through Brynglas Tunnels. It

would also reduce turning movements at the junction and would enable bus priority

measures to be introduced at the junction and along A4051 Malpas Road.

Bearing in mind the above, the proposed SSOs for modification to Junction 26 are as

follows:

• To reduce traffic flows through Brynglas Tunnels;

• To provide directions to local traffic wishing to access the motorway;

• To improve operating conditions for all traffic using the junction;

• To minimise disruption to road users during implementation;

• To improve bus journey times and reliability through the junction;

• To enhance road safety at the junction; and

• To avoid adverse impact on the environment.

Improvement to Junction 28 with Associated Works at Bassaleg and Pont Ebbw

Roundabouts

Junction 28 is a key node on the local highway network in terms of access to the motorway

and to commuter routes. It provides access to west Newport, which is a major employment

area and hence a generator of peak period traffic. It also provides access to the motorway

and the SDR from the western valleys. During peak travel times, the approaches to the

interchange are congested with delays to all who use this junction. The provision of

additional capacity at this important interchange will improve network efficiency. However,

Bassaleg Roundabout to the north is linked to Junction 28 via the A467 Forge Road, which

is heavily trafficked at peak travel times. Further efficiency gains would thus be likely to

result from improved operations at Bassaleg Roundabout. Similarly, Pont Ebbw

Roundabout to the east is linked to Junction 28 via the A48 SDR. This junction provides

access to employment sites and is currently a source of traffic congestion during peak travel

times. This impacts upon through traffic using the SDR and is a source of delays. The

reduction in delays to SDR through traffic at Pont Ebbw Roundabout would improve the

efficiency of the distributor road.

In view of the impact on the local roads of the release of suppressed demand through the

provision of additional capacity at Junction 28, there would be merit in consideration of

appropriate modification to Bassaleg Roundabout and Pont Ebbw Roundabout in tandem

with improvement to Junction 28.

The proposed Scheme Specific Objectives for the improvement of Junction 28 are as

follows:

• To increase throughput at the junction;

• To increase use of the SDR;

• To reduce delays to movements between M4 (west)/A48 (west)/A467 and the SDR;

• To minimise disruption to road users during implementation;



16




Upgrade to Steelworks Access Road (SAR)

The provision of a public highway running east/west through the Llanwern Steelworks site

would link access to Junction 23A at Magor with the SDR at Queensway Meadows. This

route would be likely to be the preferred route to the Newport Eastern Expansion Area from

the east. Depending upon the standard of road provided, this route could offer an alternative

to the motorway as a means of access to Newport from the east. This would increase

east/west highway capacity. However, the effectiveness of this as an east/west route will be

dependent upon level of service provided. This will be influenced by the type and frequency

of junctions. For instance, the inclusion of roundabouts might reduce the attractiveness of

the route for through traffic.

The Scheme Specific Objectives for the upgrade to the SAR are as follows:

• To provide additional east/west highway capacity;

• To provide an alternative route into Newport from the east;

• To improve journey times between Junction 23A and south Newport;

• To provide a diversionary route during occurrence of accidents, incidents or

maintenance works on the motorway around Newport;

• To improve access to the Newport Eastern Expansion Area; and


Incremental Improvement to the Southern Distributor Road (SDR)

The motorway is generally seen as the most attractive route into Newport from the east and

west. Observation of existing traffic movements at the motorway junctions around Newport

shows strong movements onto the motorway (west) from the A449 at Junction 24, strong

movements onto and off the motorway (east) at Junction 25A, strong movements onto and

off the motorway (west) at Junction 26 and strong movements onto and off the motorway at

Junction 28. These movements are illustrated in Figure 3.4.

In order to increase the attractiveness of the SDR as an east/west through route and/or as a

means of access into Newport, the level of service provided requires to be raised. This

would require, where possible, unimpeded through movement. To achieve this, all sources

of delay to main line traffic on the SDR need to be identified and minimised. This is likely to

require the re-modelling of some existing junctions. The approach to be adopted may be

incremental, such that those junctions where delays are greatest may be tackled as a matter

of priority. Where conditions at existing junctions are unlikely to impact upon drivers’ route

choice, no action would be required.

The proposed Scheme Specific Objectives for the incremental improvement to the SDR are

as follows:

• To reduce the average journey time end to end on the SDR;

• To improve journey time reliability;

• To eradicate significant sources of delay to main line traffic;

• To provide direction via the SDR for traffic with an origin or destination in Newport;

• To provide additional capacity for east/west movements around Newport; and


17




Figure 3.4: 2005 AM Peak Hour Traffic Movements at Motorway Junctions 24 – 28 Key:

Peak Hour Flow (vehicles per hour)

18




Improvement to B4245 Junction West of Magor

The junction between the B4245 and the steelworks access road to the west of Magor

currently results in traffic queuing back into Magor during the AM peak period. Residents of

Magor have voiced their concerns about this situation. Increased use of the access road

would exacerbate the situation. As part of the corridor enhancement package, potential to

improve the situation and to achieve network efficiency improvements is under investigation.

The proposed Scheme Specific Objectives are as follows:

• To facilitate access to the motorway at Junction 23a;

• To provide direction via the SAR for traffic with an origin or destination in Newport;

• To minimise delays to traffic using the B4245;



Improvement to Junction 29A

The A48(M) terminates immediately to the east of the westbound merge from the A48 at

Junction 29A. The existing junction is a taper merge, the dimensions of which are sub-

standard compared with the requirements of current guidance (TD 22/06). In practice, traffic

flows inbound to Cardiff on the main carriageway are disrupted during peak travel times by

merging vehicles from the minor road (the A48) joining the inside lane without sufficient

distance for speeds to adjust and efficient merge operations to occur.

The proposed Scheme Specific Objectives for improvement to Junction 29A are as follows:

• To provide a layout that conforms to current design standards;

• To avoid the need to acquire land beyond the existing highway boundary;



Strategic Park and Ride

The National Transport Plan4 states that the Welsh Assembly Government will “create a

series of strategic modal interchanges where people can park and ride or park and share,

by 2014.”

The M4 corridor would appear to be a candidate for the location of strategic modal

interchange. However, the impact that public transport has in limiting demand for motorway

capacity around Newport is currently small and previous studies5 have indicated that the

potential to reduce future demand for private transport use of the motorway is likely to be

limited. Nevertheless, the provision of Park and Ride facilities and improvement in service

levels of local public transport would have the potential to increase accessibility and travel

choice.

A number of candidate sites for strategic Park and Ride have previously been identified from

a combination of previous studies, policy documents and inspection of arising opportunities.6

The proposed Scheme Specific Objectives for option development for strategic Park and

Ride are as follows:

• To identify a site or sites with high potential to achieve significant patronage to impact

positively on congestion and sustainable travel along the M4 corridor;

4 National Transport Plan, Welsh Assembly Government, March 2010

5 New M4 Project Magor to Castleton – Assessment of Rail Measures in CAF Hybrid 2, Final Report, Arup, March 2008

6 Strategic Park and Ride, Technical Note (Draft), Arup, March 2010

19




• To maximise access to interchange between transport modes at strategic locations

along the M4 corridor;

• To provide information on travel choice, using ITS and other methods, and to provide

clear direction to Park and Ride and Park and Share facilities;

• To provide attractive, user friendly parking and transfer facilities to ensure sufficient

capacity to accommodate likely demand;

• To offer a good level of service (including tariff structure, opening hours, security,

frequency of transfer etc) so as to attract patronage; and


20




4 IMPLEMENTATION AND MONITORING

As has been referred to previously, a strength of the corridor enhancement approach is that

measures can be introduced in a phased manner. This enables flexibility so that

implementation programmes can be developed based on likely available funding. There is

also the opportunity to gain “quick wins”, where measures can be introduced in a short

timescale and can deliver immediate, tangible benefits.

Where land acquisition is necessary or statutory processes need to be followed, timescales

to implementation may be longer, or even indeterminate at the outset. Such considerations

must be taken into account in developing implementation programmes.

It will be important to monitor progress with implementation and the effect that individual

measures have as they are introduced. This monitoring process is particularly important in

this case, as the impact of individual measures may influence the implementation

programme of other measures.

To assist the monitoring process, when designing schemes, the expected outcomes as a

result of a measure should be clearly identified. When implemented, the degree to which a

measure achieves the outcomes expected will be testament to the effectiveness of the

measure in practice. Some measures may exceed expectations, whilst others may be less

effective. Either way, the knowledge of the effectiveness of performance will be useful

information to the Assembly when considering other situations.

It is recommended that an M4 CEM Monitoring Review Panel be established. This might

include representatives of the main stakeholders. Each of the involved parties would be

expected to take ownership of the proposed programme and thus to work positively towards

its successful delivery. The approach to monitoring should be “open book” to the Review

Panel, if the process is to be fully effective.

The Review Panel should meet on a six monthly basis to review progress during the early

years. It is possible that, as a result of changing circumstances, programmes may need to

be accelerated or re-scheduled and the input of the Review Panel would provide valuable

feedback to aid political, financial or technical decision-making.

Monitoring criteria7 put forward for the National Transport Plan could be used directly to

monitor the effectiveness of CEMs. These include:

• % modal share;

• Greenhouse gas emissions;

• % use of sustainable resources during construction;

• Emissions of air pollutants, number of pollution incidents, number of AQMAs;

• Accessibility to health, education, employment, retail, key settlements, visitor attractions;

• Travel time variance;

• Accidents; and

• User satisfaction.

7 National Transport Plan: WelTAG Assessment, AECOM, February 2010

21




5 SUMMARY

Arup has developed a strategy for the M4 transport corridor through south east Wales which

aims to make best use of existing capacity, improve the resilience of the network and

increase travel options. A number of Corridor Enhancement Measures (CEMs) have been

considered and an appraisal process has been developed. Each measure under

consideration has been scored against an identified set of Strategic Performance Indicators

(SPIs). These indicators have been cross-referenced against the Transport Planning

Objectives (TPOs), which were established at the WelTAG Planning Stage. The appraisal

summary table (see Table 3.1) gives an indication of the relative performance of individual

measures and, overall, indicates that a package of measures will, to a degree, address each

of the TPOs.

Based on a seven point scale (-3 to +3), each measure has been scored against 16 SPIs,

which has resulted in an aggregate unweighted score for each measure. The list of

measures in score order is shown in Table 5.1.

It is recommended that the Welsh Assembly Government give consideration to the

unweighted scores of individual measures in order to identify priorities for implementation. It

should, however, be noted that the scores quoted make no allowance for political,

economic, social or environmental weightings.

On points of detail in respect of Table 5.1, the following should be noted:

• East/West Bus Rapid Transit forms part of a citywide transport strategy for Newport and

is included in the Unitary Development Plan8 for the city; and

• Park and Ride/Parkway railway station at St Mellons is a development proposal which is

currently being promoted by a private development company. This proposal would

need the support of the rail industry. The affordability and deliverability of this proposal

will need to be established.

A number of measures are currently being investigated further and a set of Scheme Specific

Objectives (SSOs) has been drawn up for each measure being investigated. For each

measure the SSOs form the basis for appraisal of scheme options.

Finally, recommendations are made regarding the establishment of an M4 CEM Monitoring

Review Panel to assist the process of monitoring implementation of measures. It is also

suggested that the monitoring criteria put forward for the National Transport Plan could be

used to monitor the effectiveness of CEMs.

8 Newport Unitary Development Plan 1996 – 2011, Adopted, Newport City Council 2006

22




Table 5.1: CEMs in Strategic Appraisal Stage Unweighted Score Order

Measure Unweighted Score Against SPIs

At-grade improvement to the A48 Southern Distributor Road (SDR) +19

East/West Bus Rapid Transit* +19

Upgrade to Steelworks Access Road +18

Improvement to Junction 28 with associated works at Bassaleg and Pont Ebbw Roundabouts

+16

Removal of east facing slip roads and widening of west facing slip roads at Junction 26

+12

Improvement to B4245 junction west of Magor +12

Park and Ride/Parkway railway station at St Mellons** +11

Increased length of westbound merge at Junction 29A +9

Park and Ride at Severn Tunnel Junction +9

Park and Ride at Llanwern +9

Closure of Junction 27 +9

Improvement to incident and queue detection using ITS +8

Improved driver information +8

Park and Ride at Rogerstone +8

Incremental widening between Junctions 29 and 28 +7

Traffic monitoring for incident management using ITS +7

Park and Ride at Coedkernew +7

Removal of east facing slip roads at Junction 25 +6

Lane restriction with enforcement using ITS +6

Update to controlled motorway +6

Hard shoulder running/incremental widening between Junctions 28 and 27 +5

Incremental widening between Junctions 27 and 26 +5

Re-branding of driver experience on motorway +5

Park and Ride at Magor +4

Reduction in traffic noise +2

* Included in Newport Unitary Development Plan 1996 – 2011

** Private sector development proposal

23

24

Appendix A

Transport Planning Objectives

25

Transport and Strategic Regeneration Welsh Assembly Government M4 Corridor Enhancement Measures, Magor to CastletonStrategy, Appraisal and Monitoring


Page A1 Ove Arup & Partners LtdDraft 2 4 May 2010

A1 Transport Planning Objectives

The TPOs shown in Table A aim to provide a framework within which to test the relative

effectiveness of a series of possible measures that follow themes, such as:

• Public transport;

• Increasing the capacity on the motorway;

• Improving network resilience and network choice; and

• Environmental improvement/mitigation.

Table A: Transport Planning Objectives for Improving Corridor Efficiency, April 2009

Objectives Definition

TPO 1 To improve connectivity within Wales and Internationally along the east-west strategic corridor in South Wales.

TPO 2 To discourage the use of the motorway around Newport as a local distributor road.

TPO 3 To make better use of the existing highway asset.

TPO 4 To increase journey time reliability.

TPO 5 To increase travel choice for all.

TPO 6 To improve accessibility to key centres and services.

TPO 7 To improve the transport network management around Newport.

TPO 8 To improve travel safety on the transport network around Newport.

TPO 9 To improve air quality around Newport.

TPO 10 To reduce the number of people subjected to high noise levels.

TPO 11 To reduce greenhouse gas emissions per vehicle and/or person kilometre.

TPO 12 To enhance the traveller experience through the gateway to South Wales.

26

27

Appendix B


28



Page B1 Ove Arup & Partners LtdDraft 2 4 May 2010

B1 Problems with the Transport System in South East

Wales


Problems Definition

P1 There is a lack of resilience* in the road network around Newport.

P2 There is a mismatch between demand and available capacity on the motorway

around Newport.

P3 Problem P1 and P2 will worsen over time.

P4 The existing transport system acts as a constraint to economic growth.

P5 There will be capacity restrictions during essential major maintenance on the existing M4 within the next 5-10 years.

P6 HGVs do not operate efficiently on the motorway around Newport.

P7 There is an air pollution problem associated with the motorway around Newport.

P8 Traffic congestion on the M4 around Newport contributes to emission of greenhouse gases.

P9 The transport system is at increasing risk from extreme weather events.

P10 There is an environmental noise problem associated with the motorway around Newport.

P11 The existing transportation system does not meet the Wales Spatial Plan aspirations as a gateway to Wales.

P12 The existing transportation system does not meet the aspirations of the local development plans.

P13 The current accident rate on the existing M4 is higher than average.

P14 The existing M4 is a barrier to intra-regional travel.

* Resilience is the ability of a network to cope with sudden changes in demand or operation, e.g. traffic throughput could be maintained during periods of temporary disruption

29

30

Appendix C

Results of Capacity Assessments of Existing M4 (J25a - J29)

31



Page C1 Ove Arup & Partners LtdDraft 2 4 May 2010

Appendix C. Results of Capacity Assessment of Existing M4 J25a-J29

Motorway Capacity between Junctions 25a and 26

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

2005 2007 2009 2011 2013 2015 2017 2019 2021 2023 2025 2027 2029 2031

Peak hour flow

Do minimum On-line widening between J29-J24 Corridor efficiency improvement *

New M4 Practical Capacity Practical Capacity (On-line Widening)

Peak hour flow over

capacity by 2024

Congestion Reference Flow between Junctions 25a and 26

0

20000

40000

60000

80000

100000

120000

2005 2007 2009 2011 2013 2015 2017 2019 2021 2023 2025 2027 2029 2031

AADT

Do minimum On-line widening between J29-J24

Corridor efficiency improvement * New M4

85% of Congestion Reference Flow 85% of Congestion Reference Flow (On-line Widening)

Demand flow exceeds

congestion threshold by 2018

* Measures include:

Corporation Road link; Hard shoulder running between Junctions 29 and 28; Hard shoulder running between Junctions 28 and 27; Hard shoulder running between Junctions 27 and 26; Increased length of westbound merge at Junction 29A; Increased capacity of eastbound merge and westbound diverge at Junction 29; At-grade improvement to the SDR; Upgrade to Steelworks Access Road; Improvement to B4245 junction west of Magor; Improvement to Junction 28; Closure of Junction 27 with associated works at Bassaleg Roundabout; Removal of East facing slip roads and widening of West facing slip roads at Junction 26; and Removal of East facing slip roads at Junction 25.

32




Appendix C: Results of Capacity Assessment of Existing M4 J26-J29 (continued)

Motorway Capacity between Junctions 26 and 27

0

1000

2000

3000

4000

5000

6000

7000

8000

2005 2007 2009 2011 2013 2015 2017 2019 2021 2023 2025 2027 2029 2031

Peak hour flow



Peak hour flow remains

under capacity in 2031

Congestion Reference Flow between Junctions 26 and 27

0

20000

40000

60000

80000

100000

120000

140000

160000

2005 2007 2009 2011 2013 2015 2017 2019 2021 2023 2025 2027 2029 2031

AADT




Demand flow remains under

congestion threshold in 2031

* Measures include:


33






0

1000

2000

3000

4000

5000

6000

7000

8000

2005 2007 2009 2011 2013 2015 2017 2019 2021 2023 2025 2027 2029 2031

Peak hour flow






0

20000

40000

60000

80000

100000

120000

140000

160000

2005 2007 2009 2011 2013 2015 2017 2019 2021 2023 2025 2027 2029 2031

AADT






* Measures include:


34






0

1000

2000

3000

4000

5000

6000

7000

8000

2005 2007 2009 2011 2013 2015 2017 2019 2021 2023 2025 2027 2029 2031

Peak hour flow





* Measures include:



0

20000

40000

60000

80000

100000

120000

140000

160000

2005 2007 2009 2011 2013 2015 2017 2019 2021 2023 2025 2027 2029 2031

AADT






35

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