A PERSPECTIVE ON APPLICATION OF A PAIR OF PLANNING AND MICRO SIMULATION MODELS: EXPERIENCE FROM...
-
Upload
christopher-hammond -
Category
Documents
-
view
214 -
download
0
Transcript of A PERSPECTIVE ON APPLICATION OF A PAIR OF PLANNING AND MICRO SIMULATION MODELS: EXPERIENCE FROM...
A PERSPECTIVE ON APPLICATION OF A PAIR OF PLANNING AND MICRO SIMULATION MODELS: EXPERIENCE FROM I-405 CORRIDOR STUDY
PROGRAM
Murli K. Adury
Youssef Dehghani
Cathy Strombom
Parsons Brinckerhoff Quade & Douglas, Inc.
Seattle, WA, USA
Project Context
I-405 Corridor Program:» I-405 was built in 70s to alleviate
congestion along I-5» Experiencing unexpectedly high rate of
growth from high tech sector (e.g., Microsoft) within I-405 corridor – resulting in high levels of congestion
» Undertaking comprehensive alternatives analysis
Project Area Map
Why Micro Simulation?
Be able to evaluate realty checks on capacity enhancement elements of the preferred alternative – balancing capacity needs on arterials vs. I-405 thru better diversion mechanism
Be able to refine and/or modify capacity enhancement elements of the preferred alternative
Be able to highlight potential deficiencies – e.g., lid concept thru downtown Bellevue
Why Integration?
WSDOT undertook a rigorous evaluation of the existing micro simulation software programs
Integration most suited because of its capabilities for:» Micro simulation analysis at corridor level» Equilibrium route diversion analysis» State-of-the-art methodology for traffic simulation
analysis» Being able to interface with the existing regional
planning model databases
Model Development Process
Network preparation/calibration Data collection
» Details of network geometry» Signal timings » Traffic counts
Trip table development Model validation analysis Model application
Network Development
Included only:» I-405 & major parallel arterials (3000 links)» Major intersections (100 signalized intersections)
Initially used default parameters & refined further during validation process
Most difficult tasks:» Developing a network to fit INTEGRATION limits» Data input for microsimulation – lane geometry,
signal data, turn pockets, physical attributes of roadway system
Trip Table Development
Regional model produced PM peak (hour) vehicle trip tables for HOVs and Non-HOVs
Post regional modeling procedure:» Direction peak-hour base year counts were seeded
on designated links on I-405 and arterials» Matrix adjustment macro DEMADJ.MAC
developed Heinz Spiess was used to update original matrix
» Resulting O-D matrix was imported into the Integration model environment
Model Validation Analysis
Initial analysis indicated that study area network needed to be streamlined:» Secondary arterials were removed» Secondary signalized intersections were also
removed Hourly counts exhibited wide variations across
weekdays and months:» Overall average and max/min limits were established
Attempts were made to “optimize” signal timing coordination
Model Validation Analysis- Continued -
Prepared summary system-wide measure:» Peak-hour demand input as % of total demand» % vehicles reached destinations» VMTs/VHTs» Total delays & stop delays
Prepared link-level summaries:» Total flow» Travel time» Queue length
Model Validation Analysis- Continued -
Model Flow Rate vs Average Peak Hour Count(I-405 NB between SR 167 and SR 169)
0
1000
2000
3000
4000
5000
6000
0 15 30 45 60 75 90
Simulation Time (Time = 0 to 90 minutes)
Flo
w R
ate
(v
ph
)
Min Count
Max Count
Avg Count
Model
Model Validation Analysis- Continued -
Comparative analysis of queue build-up against recurring bottleneck areas posted on the WSDOT website
Performed additional network refinement accordingly
Accomplished reasonable base year validation results
Model Validation Analysis- Continued -
Model Application
In I-405 EMME/2 Model» Developed 2020 network for the preferred
alternative» Prepared 2020 Travel Forecasts» Developed 2020 peak-hour trip table
– Prepared base year to 2020 zone-to-zone growth rates
– Applied implied zone-to-zone growth rate to the base year adjusted peak-hour trip table
Model Application- Continued -
Provided insights into the alternatives analysis process
Highlighted initially proposed improvement plan/conceptual design deficiencies within the project corridor
Identified potential bottleneck areas Integration modeling achieved its
purpose
Lessons Learned
Allow adequate time to:» Define objectives for why needing to do
micro simulation and for what purpose» Identify appropriate software program and
its limits accordingly Identify study area carefully for:
» Boundaries» Network details (no. of links & intersections)
Lessons Learned - Continued
Assess potential interface with other tools (e.g., regional model databases, network editing, etc.)
Trip matrices need to go through an adjustment process reflecting actual counts
Assess data needs carefully Micro simulation model is data hungry & time
consuming