Dynamic Traffic Assignment:Integrating Dynameq into Long Range Planning Studies

Model City 2011 – Portland, Oregon

Richard Walker - Portland MetroScott Higgins, Peter Bosa – Portland Metro

Introduction

Current DTA Applications• Immediate project impacts (e.g., lane

closures, ramp openings, construction impacts, etc.)

• Short term horizonDTA as a planning tool• Alternative analysis (multiple scenarios,

comparative evaluation metrics)• Long term horizon

Overview

1. Motivation for change2. Assignment metrics3. Challenges4. Status5. Future plans and applications

Motivation for Change• Congestion is a given. Assignment tools

need to operate within that environment.• Decision metrics are changing• Queuing and path choice effects• Duration of congestion• Temporal characteristics matter

Assignment Metrics -Static• Static assignment– Served us well, but– Shortcomings are becoming

problematic

Metrics - Static

V/C ratios – PM 2 hr. Can exceed 1.0. Represent average conditions

Metrics - Static

Average speeds – PM 2 hr

Metrics - Static

PM 2-hr volume flows based upon average speeds for time period

Assignment Metrics - DTA• Dynameq (DTA)– Addresses many of the shortcomings

Metrics - DTA

Incremental volumes: 6:30 – 6:35 p.m.

Metrics - DTA

Incremental volumes: 6:35 to 6:40 p.m.

Metrics - DTA

Incremental volumes: 6:40 to 6:45 p.m.

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Metrics – DTATemporal characteristics

Static

DTA

Detector

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lane

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Metrics – DTA

Temporal characteristics

Metrics - DTA

Queuing effects – 6:35 to 6:40 pm

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Metrics – DTATime –space diagram

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Metrics - DTATravel time trajectories

Metrics - DTA• Potential for more “realistic” turns at

intersections• Signal plans• Accounts for conflicting moves

• Visualization/animation• Pricing strategies• Reliability

Challenges

• Building staff expertise• Adding network attributes•Validation more work• Base vs. future year temporal profile• Scenario preparation time• Computer run time

Status

Staff developmentRead (DTA Primer)Observe other studiesDevelop expertise with other DTA

software. (Note: We have recently added Dynameq capability).

Dynameq – tutorial and formal trainingNetwork development

Geometries Attributes (signal locations, lanes/turn

bays, etc.)

Status

Regional application - DynusTFreeway focus, major highwaysConsistent with cutline countso Temporal profile checks

Portal data - PSUINRIX

o 2035 application

Status

Corridor application – DynameqRecent purchase – very early stagesSubarea has been created with INRO’s

assistanceKnowledge buildingo Add signal plans in the heart of the

corridor study area. Simpler intersection treatment outside the focal point.

o 2035 applicationo Alternative analysis

Near Term Applications

East Metro Connection Plan– Dynameq corridor study– “test” application

SW Corridor Study– Transit study– Lane removals

Future Plans• Elevate DTA to “everyday tool” status• Use DTA to provide better input to

microsimulation• Link to MOVES• Investigate transit treatment in DTA• Link to tour based model– “DASH” model very temporally based

Thank you

Questions?