Transportation Planning and Modeling

Transportation planning is a field involved with the evaluation, assessment, design and siting of transportation facilities (generally streets, highways, footpaths, bike lanes and public transport lines). – Wikipedia, Aug 29, 2010 Image: public domain

Rational Planning Method

– defining goals and objectives,

– identifying problems,

– generating alternatives,

– evaluating alternatives, and

– developing plans

Image: GNU Free Documentation LicenseDaniel Schwen, the copyright holder

Des Moines MPOhttp://www.dmampo.org/

Planning Options

• Short run– TSM– TDM– Access Mgmt.– Congestion Mgmt.

• Long Run– Construction– Land use

• Future?– Pricing– Technology (ITS, fuels)

Congestion Pricing• http://www.streetfilms.org/archives/campaign-for-new-yorks-future-congestion-pricing/

Why we don’t use congestion pricing: http://planningresearch.blogspot.com/2007/03/manville-on-why-we-dont-use-congestion.html

Travel demand modeling

• Evaluating alternatives requires– Estimated travel demand (trips)– Estimated trip lengths– Estimated modal shares– Estimated travel speeds– Estimated travel delays– Estimate air quality, noise and energy impacts

• Need a systematic process

“Four” step model

optional

sometimes omitted

Data collection

• Demographic/Socioeconomic

• Transportation system

• Travel behavior/propensity/desires– Surveys

Study area/zone slide

Des Moines MPO Boundary

Zones (TAZs)

Travel Demand Modeling (Forecasting)

• What is travel “demand”?• Three factors

– Land use– Socioeconomics and demographics– Transportation services

(TTYP name 3characteristicsof these factorsthat affect demand)

Trip Generation

• Determine number of “trip ends”

• Methods– Cross Classification (tables)– Rates based on activity units (ITE) – Regression

Trip Distribution

• Determine origin and destination of trips

• Methods– Gravity model (Need a good shortest path

algorithm)– Growth factor models

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Find the shortest path from node to all other nodes (from Garber and Hoel)1

Yellow numbers represent link travel times in minutes3

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FINAL1

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From: Davison E. SoperUniv of Oregon

©1995 - 2008, AMERICAN PHYSICAL SOCIETYAPS encourages the redistribution of the materials included in this newspaper provided that attribution to the source is noted and the materials are not truncated or changed.

http://mitchlanaillustration.blogspot.com

Mode Choice (Split)

• Which mode (transit, walk, carpool,drive alone, …) will be used?

• Methods– Direct generation– Trip end models– Trip interchange models

Traffic Assignment

• Which route will the trips take?

• Methods– Minimum path (distance or time)– Capacity restrained

• Need a good shortest path algorithm