Estimating Congestion Costs Estimating Congestion Costs Using a Transportation Using a Transportation

Demand Model of Edmonton, Demand Model of Edmonton, CanadaCanada

C.R. BlaschukC.R. BlaschukInstitute for Advanced Policy ResearchInstitute for Advanced Policy Research

University of CalgaryUniversity of Calgary

A.T. BrownleeA.T. BrownleeTransportation DepartmentTransportation Department

City of EdmontonCity of Edmonton

J.D. HuntJ.D. HuntInstitute for Advanced Policy ResearchInstitute for Advanced Policy Research

University of CalgaryUniversity of Calgary

Presented at the 11Presented at the 11thth TRB National Transportation Planning Applications Conference TRB National Transportation Planning Applications ConferenceDaytona Beach, FLDaytona Beach, FL

May 8, 2007May 8, 2007

OutlineOutline

IntroductionIntroduction– Overview of Congestion PricingOverview of Congestion Pricing– Edmonton ModelEdmonton Model

MethodMethod– Scheme consideredScheme considered– Modifying Volume-Delay FunctionsModifying Volume-Delay Functions– Composite Utility ApproachComposite Utility Approach

ResultsResults

IntroductionIntroduction

GoalsGoals Quantify total economic costs from congestionQuantify total economic costs from congestion

– Theoretical viewpoint onlyTheoretical viewpoint only– Use values as a basis for further considerationUse values as a basis for further consideration

Easy implementation in an existing modelEasy implementation in an existing model Results from a model used in everyday Results from a model used in everyday

engineering applicationsengineering applications Useful resultsUseful results

IntroductionIntroduction

Quantifying CongestionQuantifying Congestion Two approachesTwo approaches

– EngineeringEngineering Differences from free-flow or acceptable conditionsDifferences from free-flow or acceptable conditions

– EconomicEconomic Deadweight losses due to inefficient pricing of roadsDeadweight losses due to inefficient pricing of roads

Economic approach usedEconomic approach used

flow of vehicles

generalized cost

Demand

Average Private Costs

Marginal TotalCosts

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F

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Market view of flow of vehicles on a section of roadway; with congestion deadweight loss shown

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Economic ApproachEconomic Approach

flow of vehicles

generalized cost

Demand

Average Private Costs

Marginal TotalCosts

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Market view of flow of vehicles on a section of roadway; with congestion deadweight loss shown

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Unpriced Equilibrium

flow of vehicles

generalized cost

Demand

Average Private Costs

Marginal TotalCosts

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Market view of flow of vehicles on a section of roadway; with congestion deadweight loss shown

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Gap in costs (cost to society vs cost driver pays)

flow of vehicles

generalized cost

Demand

Average Private Costs

Marginal TotalCosts

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F

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Market view of flow of vehicles on a section of roadway; with congestion deadweight loss shown

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Priced Equilibirum

Tolls Collected

flow of vehicles

generalized cost

Demand

Average Private Costs

Marginal TotalCosts

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Market view of flow of vehicles on a section of roadway; with congestion deadweight loss shown

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Deadweight Loss (DWL)

IntroductionIntroduction

Used the Regional Transportation Model of Used the Regional Transportation Model of Edmonton, CanadaEdmonton, Canada

Base ConditionsBase ConditionsEdmonton Region - 2005

Population 1,016,000

Total Trips 3,855,000

AM Peak (7:00 – 9:00) 532,000

PM Peak (16:00 – 18:00) 643,000

Rest of Day 2,680,000

VHT (Daily) 605000

IntroductionIntroduction

Edmonton Regional Transportation Model (RTM)Edmonton Regional Transportation Model (RTM) Built in EMME/2Built in EMME/2 1,091 Zones, 15,400 Links1,091 Zones, 15,400 Links Enhanced 4-Step ModelEnhanced 4-Step Model Rich feedback mechanismsRich feedback mechanisms Time of Day and Peak SpreadingTime of Day and Peak Spreading 24 Hours (5 Time Periods)24 Hours (5 Time Periods) 25 Person Group / Trip Type Combinations25 Person Group / Trip Type Combinations

– Ex. Adult Home-to-Work, Adult Work-to-Home, etcEx. Adult Home-to-Work, Adult Work-to-Home, etc Nested Logit StructureNested Logit Structure

24 Hour Trip Destination Choice:

j(2)

origin zone i

j(n)....j(1)

destination zone j

Time of Day Choice:

am off

daily i-j

pm

Mode Choice:

car1 car2 car3

car p&r

transit auto

mechanical

cycle

metabolic

walk

time of day i-j

Peak Crown vs Peak Shoulder Choice:

peak crown

car mode i-j

peak shoulder

Conceptual nested logit model structure

MethodMethod

Apply congestion charges network-wideApply congestion charges network-wide– Toll all auto links to prevent toll evasionToll all auto links to prevent toll evasion– Can calculate theoretical maximum costsCan calculate theoretical maximum costs– No tolls for public transitNo tolls for public transit

Implement tolls by modifying volume-delay Implement tolls by modifying volume-delay functionsfunctions– VDFs represent average costs AC(v) at volume vVDFs represent average costs AC(v) at volume v– Total costs TC(v) = AC(v)*vTotal costs TC(v) = AC(v)*v– Marginal costs MC(v) = d[TC(v)]/d[v]Marginal costs MC(v) = d[TC(v)]/d[v]

MethodMethod

Two runs neededTwo runs needed Base – 2005 ModelBase – 2005 Model Congestion Pricing – Apply Marginal Cost Congestion Pricing – Apply Marginal Cost

Functions to Base 2005 modelFunctions to Base 2005 model

First look at results on a link-based levelFirst look at results on a link-based level

MethodMethod

FindingsFindings Volumes typically decreased on major links with Volumes typically decreased on major links with

addition of tolls.addition of tolls. Volumes sometimes increased on minor links with Volumes sometimes increased on minor links with

addition of tolls.addition of tolls. End result: demand is shiftingEnd result: demand is shifting

– Link based analysis not an appropriate methodLink based analysis not an appropriate method– Not possible to calculate system-wide deadweight loss Not possible to calculate system-wide deadweight loss

flow of vehicles

generalized cost

BaseDemand

Average VariableCosts

Marginal TotalCosts

D EO

MethodMethod

Why would demand shift?Why would demand shift? Network-wide toll increases desire to make shorter Network-wide toll increases desire to make shorter

trips (to closer destinations)trips (to closer destinations) Desire to travel at different times of day and use Desire to travel at different times of day and use

different modesdifferent modes Increased costs on less congested links less than Increased costs on less congested links less than

increases on more congested links.increases on more congested links.

MethodMethod

Need to look at costs where demand wont shiftNeed to look at costs where demand wont shift Assume demand for travel stays the sameAssume demand for travel stays the same Look at changes in composite utilityLook at changes in composite utility

– Composite Utility provides information on costs of choices Composite Utility provides information on costs of choices from all alternatives at lower levels in the nested logit from all alternatives at lower levels in the nested logit modelmodel

– Composite Utility of accessibility to Origins/Destinations is Composite Utility of accessibility to Origins/Destinations is part of trip generation level in the logit modelpart of trip generation level in the logit model

– Can look at changes in the composite utility of Can look at changes in the composite utility of accessibility to determine how much travel is changing accessibility to determine how much travel is changing without changing demand for travel.without changing demand for travel.

MethodMethod

Calculating Composite Utility of AccessibilityCalculating Composite Utility of Accessibility Need 4 PointsNeed 4 Points

1.1. CU for base caseCU for base case

2.2. CU for congestion pricing caseCU for congestion pricing case

3.3. What CU would be with congestion pricing at base What CU would be with congestion pricing at base volumesvolumes

4.4. What CU would be with base pricing at congestion What CU would be with base pricing at congestion pricing volumespricing volumes

flow of vehicles

generalized cost

Demand

Average Private Costs

Marginal TotalCosts

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Market view of flow of vehicles on a section of roadway; with congestion deadweight loss shown

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Want composite utility for these points

MethodMethod

Know composite utility from cases 1 and 2 (part of Know composite utility from cases 1 and 2 (part of model run calculations).model run calculations).

For case 3For case 3– Replace average costs with marginal costsReplace average costs with marginal costs– Reassign to get new travel costsReassign to get new travel costs– Recalculate composite utility based off new travel costsRecalculate composite utility based off new travel costs

For case 4For case 4– Replace marginal costs with average costsReplace marginal costs with average costs– Reassign to get new travel costsReassign to get new travel costs– Recalculate composite utility based off new travel costsRecalculate composite utility based off new travel costs

MethodMethod

Results measured in changes of composite utility Results measured in changes of composite utility valuesvalues

To convert to dollarsTo convert to dollars– Raise operating costs by $1Raise operating costs by $1– Observe change in utilities corresponding to $1 change Observe change in utilities corresponding to $1 change

to get change in utility/$to get change in utility/$

Using change in utility and volumes, can obtain all Using change in utility and volumes, can obtain all necessary values.necessary values.

ResultsResults2005 Trips - Difference (Congestion Pricing - Base Run)

Mode AM PM OFF Daily

Daily Percent Change

Car Driver -3,600 -7,000 -8,200 -18,800 -0.9%

Car Passenger -300 -1,400 -1,300 -3,000 -0.4%

Transit 3,300 2,800 4,900 11,000 4.0%

Walk / Bike 500 900 3,700 5,100 1.6%

TOTAL -100 -4,700 -900 -5,700 -0.2%

ResultsResults

Decrease in auto trips across the dayDecrease in auto trips across the day– Some peak spreading evidentSome peak spreading evident– PM experienced biggest lossesPM experienced biggest losses

Likely most congested time of dayLikely most congested time of day

Transit absorbs most of the displaced auto Transit absorbs most of the displaced auto tripstrips

About 5,700 trips leave the systemAbout 5,700 trips leave the system

ResultsResults

Total daily tolls collected is ~$750,000 / dayTotal daily tolls collected is ~$750,000 / day– Comparable to other studiesComparable to other studies

Daily deadweight loss of ~$1,300 / dayDaily deadweight loss of ~$1,300 / day– Seems low at first glanceSeems low at first glance– Increasing inputs by 30% lead to a deadweight Increasing inputs by 30% lead to a deadweight

loss of $7,000 / dayloss of $7,000 / day An increase of over 500%An increase of over 500%

ResultsResults

Deadweight loss values low, but magnitude Deadweight loss values low, but magnitude comparable to other studiescomparable to other studies– Limited previous work calculating deadweight Limited previous work calculating deadweight

loss valuesloss values– Focus has been more on ‘eliminating’ Focus has been more on ‘eliminating’

deadweight loss by calculating tolls collected deadweight loss by calculating tolls collected and costs to drivers.and costs to drivers.

ResultsResults

Possible reasons for a low deadweight lossPossible reasons for a low deadweight loss– Most congestion in Edmonton could be efficientMost congestion in Edmonton could be efficient– Edmonton might not be that congestedEdmonton might not be that congested– Large amount of capacity in transportation Large amount of capacity in transportation

system that could absorb most of the system that could absorb most of the congestion pricing impactscongestion pricing impacts

ResultsResults

Must keep in mind the difference in Must keep in mind the difference in definition of congestion costsdefinition of congestion costs– Engineering costs calculated from composite Engineering costs calculated from composite

utility approach to be ~$180,000 / dayutility approach to be ~$180,000 / day– Would equal about $45 million / year for Would equal about $45 million / year for

weekdays onlyweekdays only– Much different from economic costs, but is Much different from economic costs, but is

really answering a different question than the really answering a different question than the economic approacheconomic approach

ConclusionsConclusions

Deadweight loss can be used as an initial criteria Deadweight loss can be used as an initial criteria for consideration of congestion pricing schemesfor consideration of congestion pricing schemes– Value may be too small for Edmonton Value may be too small for Edmonton

Deadweight loss looks to make up a very small Deadweight loss looks to make up a very small part of the costs of congestion using this approachpart of the costs of congestion using this approach– Suggests most congestion is efficientSuggests most congestion is efficient

Further application of method on models of other Further application of method on models of other cities may reveal more about deadweight losscities may reveal more about deadweight loss

Questions?Questions?