Dynamic Traffic
Assignment:
Integrating Dynameq into Long
Range Planning Studies
Model City 2011 – Portland, Oregon
Richard Walker - Portland Metro
Scott Higgins, Peter Bosa – Portland Metro
Introduction
Current DTA Applications
• Immediate project impacts (e.g., lane
closures, ramp openings, construction
impacts, etc.)
• Short term horizon
DTA as a planning tool
• Alternative analysis (multiple scenarios,
comparative evaluation metrics)
• Long term horizon
Overview
1.
2.
3.
4.
5.
Motivation for change
Assignment metrics
Challenges
Status
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.
Metrics – DTA
Vehicles per lane per hour
Temporal characteristics
Detector
DTA
Static
13
Metrics – DTA
Temporal characteristics
14
Metrics - DTA
Queuing effects – 6:35 to 6:40 pm
Metrics – DTA
Time –space diagram
16
Metrics - DTA
Travel time trajectories
17
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 development
Read (DTA Primer)
Observe other studies
Develop expertise with other DTA
software. (Note: We have recently
added Dynameq capability).
Dynameq – tutorial and formal training
Network development
Geometries
Attributes (signal locations, lanes/turn
bays, etc.)
Status
Regional application - DynusT
Freeway focus, major highways
Consistent with cutline counts
o Temporal profile checks
Portal data - PSU
INRIX
o 2035 application
Status
Corridor application – Dynameq
Recent purchase – very early stages
Subarea has been created with INRO’s
assistance
Knowledge building
o Add signal plans in the heart of the
corridor study area. Simpler intersection
treatment outside the focal point.
o 2035 application
o 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?