Forecasting and Evaluating Network Growth

David LevinsonNorah Montes de OcaFeng Xie

Introduction

• Build empirically-based network growth prediction models that address the questions:

• Will “business as usual” network construction decision rules produce desirable networks?

• Will new decision rules produce improved networks?• Should policies be changed to direct future network growth in a better direction?

• Should policies be changed to produce networks that will generate the best performance measures?

• Results would let decision makers see how current investment decision rules impact or limit future choices.

Movie

If They Come, Will You Build It?

The Base-year Network

(T0=1990)Trip Generation

Shortest Path Finding

Trip Distribution

SUE Traffic Assignment

Calculating MOEs

Ranking by jurisdictions

Investing by jurisdictions

Updating TAZ information

Travel Demand Forecasting Models

Updating Network Capacity, Hierarchy,

Topology

Investment Models

Budget Models

T=T+5

SONG 2.0 Flowchart

Flowchart of Investment Models

State/County Budget Models

• State budget model is estimated by regressing expenditures on state trunk highways by Mn/DOT or Met Council from 2000 to 2004 on statewide VKT and population. ($0.006/vkt)

• County budget model is estimated by regressing expenditures on county state-aid highways and county roads in 1990, 1995, 2000, and 2003 on county statistics such as VKT and #households.

Cost Model• From Levinson and Karamalaputi (2003).

MethodologyMethodology• Face to face interviews

* Using open-ended questions

• Who was interviewed?* Minnesota Department of Transportation- Program Management Department* Metropolitan Council-Planning Management

Department* Metro Area Managers* County Engineers and staff* City - Capital and Management Department

Questionnaire• Procedure for a project to

be approved for construction?

• Most important policies to look at when making decisions?

• Main criteria?• Performance measures

considered?• Ranking system existence?• Changes in criteria from

the past to actual?• Informal procedures?• Role of politicians in the

decision-making process?

Processes

Formal

* Structured process* Ranking system through point allocation* Task forces-committees

Informal

* Priorities•safety,preservation, capacity, •social and economic impacts, •community and agency involvement•Benefit/cost ratio, etc.

* No Ranking System

Informal ProcessesJurisdictions priorities and decision making:

•“ benefit/cost ratio > 1”•“ AADT > 15,000 on 3-lane roadways” (safety reasons)•“ Intersection volumes up to 7,500 vehicles per day”

•“Implementation of policy, strategy and investment level”•“Project development time”•“Most beneficial project for the system”•“Matching funds from local jurisdictions”

Formal Processes

1. Reduction in SOV trips and/or VMT 0-75 0-100 2. Reduction of vehicle emissions 0-100 0-150 3. Measure of project effectiveness 0-300 0-300B. Congestion Mitigation 200 350 1. Congestion/increase hourly person reduction 0-100 0-175 2. Traffic congestion reduction 0-100 0-175C. Service Efficiency and productivity 250 - 1. Service efficiency 0-125 -

2. Productivity 0-125 -

D. Regional Transit Priorities 300 - 1. Corridor priority (as ranked in 2030 TPP) 0-100 - 2. Location Suitability & Market Area Demand 0-100 - 3. Integration with existing Infrastructure 0-100 -

E. Development Framework Implementation 200 200

1. Employment, housing and transportation integration 0-200 0-200

a) Intensity 60 75

b) Linkages 60 75

c) Brownfields & Natural Resources 40 50

d) Affordable/Life Cycle housing 40 -

F. Maturity of project concept 100 100

TOTAL 1,525 1,200

A. Reduction in carbon monoxide (CO), nitrogen oxide (Nox), and volatile organic compound (VOC) emissions

475 550

Transit expansion

Demand or System

Management

Project ID NumberPoints

Project PriorityLevel of NeedCritical 51-60Significant 41-50Important 21-40Desirable 0-20

In adopted Five Year Plan2006 302007-2009 202010 10New for 2006-2009 0

Integrated Project 10

Sub-Total Project Priority

Contributions to City Goals/Objs:Strong Contribution 46-70Moderate Contribution 16-45Little or No Contribution 0-15

Operating Costs: -25 to +25'

Sub-total Goals & Operating Costs

Qualitative Criteria:Neighborhood Livability & Safety 0-15Public benefit 0-15Capital Cost/Customer Service Delivery 0-15Environmental Quality 0-15Collaboration & Leveraging 0-15Effect on Tax Base & Job Creation 0-15Intellectual & Cultural Implications 0-15

Sub-Total Qualitative

Total Rating Points300

PossibleSource: Capital Long Range Improvement Committee. 2005 Capital Guidelines

CLIC Rating form

PERFORMANCE MEASUREPOINTSCapacity V/C ratio 100

Pavement 100

Safety 100

Municipal support 100

DETAILS

for example:

Pavement quality indexRatio of project crash rate to county average

=(ADDT X 0.10)/Capacity

City council resolution supports ISTEA application…………………………………….…………50City staff gives verbal support for project…..…………20

City approves preliminary design and commits to cost share greater than required by county policy………………………………………………..…..100

>5=100 points, >3=90, >20=80…<.50=0

Ratio of 10% AADT to current capacity

AADT=11900Current capacity/hr=1200Ratio=0.99Normalized score=651.52 = 100 points0.67 = 44 pointsPavement Condition IndexPresent Service-ability rating rideability

A. Relative Importance of the route 0-100 0-100 0-100 0-150 0-100B. Deficiencies and Solutions on category 425 425 425 375 425 1. Crash reduction - 0-150 0-150 0-100 0-150 On principal Arterial 0-50 - - - - On the reliever 0-50 - - - - 2. Access Management 0-125 0-175 0-125 0-125 0-175

3. Air Quality 0-100 0-50good

movement 0-75

0-100 0-50

4. Congestion Reduction - 0-50shoulder

improvement 0-75

0-50 0-50

On principal Arterial 0-50 - - - - On the reliever 0-50 - - - -C. Cost Effectiveness 275 275 275 275 275 1. Crash reduction 0-125 0-125 0-125 0-125 0-125

2. Congestion Reduction 0-75 0-75good

movement 0-75

0-75 0-75

3. Air Quality 0-75 0-75shoulder

improvement 0-75

0-75 0-75

D. Development Framework Implementation 300 300 300 300 300 1. Employment, housing and transportation integration0-200 0-200 0-200 0-200 0-200 a) Intensity 60 60 60 60 60 b) Linkages 60 60 60 60 60 c) Brownfields & Natural Resources 40 40 40 40 40 d) Affordable/Life Cycle housing 40 40 40 40 40 2. Integration of modes 0-100 0-100 0-100 0-100 0-100E. Maturity of project concept 0-100 0-100 0-100 0-100 0-100

TOTAL 1,200 1,200 1,200 1,200 1,200

Non-freeway Principal Arterial

Reliever ExpanderConnectorAugmenter

Flowcharts-Informal processesRoadways under

County’s jurisdiction

Project solicitation

ADT>15,000

3 lane-roads

Scott County

Application review

SafetyAverage Daily Traffic (ADT)

Project intop 200

high crash location list

Project approval

Reapplication?

Project construction

End

yesyes

yes

nono

yes

no

no

Flowcharts - Formal Processes - CityMinneapolis streets

Project solicitation

City of Minneapolis

Application review

Reapplication?

End

Compute scores

Highest scored project selection

Allocation of funding availability

Project approval

Project construction

yes

no no

yes

Coded Decision Rules • Flowcharts that describe the decision-making process of jurisdictions with regard to road investment• Coded if-then rules of each jurisdiction• Rules of continuous scores that ensure a project gets a unique score from a jurisdiction

• Example://ORIGINAL RULE:if(AADT>30000)juris_score[1][i]+=50;//if(AADT >20000)juris_score[1][i]+=38;//else if (AADT >10000)juris_score[1][i]+=25;

if(adt>30000)juris_score[1][i]+=Math.min(50,38+(50-38)*(AADT -30000)/(100000-30000));else if(adt>20000)juris_score[1][i]+=25+(38-25)*(AADT -20000)/(30000-20000);else if (adt>10000)juris_score[1][i]+=0+(25-0)*(AADT -10000)/(20000-10000);

Legacy Links

Constraints

Scenario Expansion Decision Rules

New Construction Decision Rules

Total Budget

Expansion Construction Budget Split

New Link Choice Set

1 Stated Revealed Standard 50/50 Legacy 2 Most

structured Revealed Standard 50/50 Legacy

3 Least structured

Revealed Standard 50/50 Legacy

4 Stated Revealed Scenarios 50/50 Legacy 5 Stated Revealed Standard 25/75 Legacy 6 Revealed Revealed Standard 50/50 Legacy 7 Revealed Revealed Standard 50/50 All

potential

Scenarios Tested

Scenario 1.

Baseline - State

Scenario 4.

Budget Increase400% - State

Scenario 6. LK

(legacy links) Model - State

Scenario 7. LK (new

choice set)

Model - State

State - Link Expansion

0.00

100.00

200.00

300.00

400.00

500.00

600.00

2005 2010 2015 2020 2025 2030 Year

Lane kilometer

Scenario 1. Baseline Scenario 3. Least Structured Scenario 4c. Increase400

Scenario 4e. Decrease25 Scenario 6. LK-Expansion Scenario 7. LK-New Construction

State Link Expansion

MOE: VKTMeasure of Effectiveness : Vehicle Kilometer Travel

-300

-200

-100

0

100

200

300

400

2005 2010 2015 2020 2025 2030

in Millions

Year

Differences

Scenario 2 - Scenario 1 Scenario 3 - Scenario 1 Scenario 4c - Scenario 1

Scenario 5 - Scenario 1 Scenario 6 - Scenario 1 Scenario 7 - Scenario 1

MOE: VHT

Measure of Effectiveness : Vehicle Hour Travel

-400

-300

-200

-100

0

100

200

300

400

500

2005 2010 2015 2020 2025 2030

in Millions

Year

Difererences

Scenario 2 - Scenario 1 Scenario 3 - Scenario 1 Scenario 4c - Scenario 1

Scenario 5 - Scenario 1 Scenario 6 - Scenario 1 Scenario 7 - Scenario 1

General Conclusions• Perception gap on

decision making process.• References to official

documents about safety, capacity, pavement conditions, and so on, but not a clear answer.

• In the past, projects selected on the engineer’s perception. However, safety issues, road conditions and capacity were present in the engineer’s minds.

• Levels of government with no ranking system - main criterion based on performance measures.

• Safety-most important.

• Counties containing Metropolitan Area center have a more formal decision-making process and a ranking system.

Conclusions-continued• Mn/DOT has backed away from

a formal process as described in the 1997 Transportation System Plan. Now more informal, less quantitative process = Decrement in transparency.

• At State level the biggest concern is what every day transportation system user notices = level of congestion and a comfortable ride.

• Some jurisdictions declined to endorse flowcharts presented, not providing alternatives.Main reason………….political & community concern

• As budget rises:• VKT rises• Network expands• Accessibility increases

• Users spend less time on the road

• VHT declines