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 l 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? l 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 l Be able to refine and/or modify capacity enhancement elements of the preferred alternative l Be able to highlight potential deficiencies – e.g., lid concept thru downtown Bellevue

Why Integration? l WSDOT undertook a rigorous evaluation of the existing micro simulation software programs l 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 l Network preparation/calibration l Data collection »Details of network geometry »Signal timings »Traffic counts l Trip table development l Model validation analysis l Model application

Network Development l Included only: »I-405 & major parallel arterials (3000 links) »Major intersections (100 signalized intersections) l Initially used default parameters & refined further during validation process l 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 l Regional model produced PM peak (hour) vehicle trip tables for HOVs and Non-HOVs l 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 l Initial analysis indicated that study area network needed to be streamlined: »Secondary arterials were removed »Secondary signalized intersections were also removed l Hourly counts exhibited wide variations across weekdays and months: »Overall average and max/min limits were established l Attempts were made to optimize signal timing coordination

Model Validation Analysis - Continued - l Prepared summary system-wide measure: »Peak-hour demand input as % of total demand »% vehicles reached destinations »VMTs/VHTs »Total delays & stop delays l Prepared link-level summaries: »Total flow »Travel time »Queue length

Model Validation Analysis - Continued -

l Comparative analysis of queue build-up against recurring bottleneck areas posted on the WSDOT website l Performed additional network refinement accordingly l Accomplished reasonable base year validation results

Model Validation Analysis - Continued -

Model Application l 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 - l Provided insights into the alternatives analysis process l Highlighted initially proposed improvement plan/conceptual design deficiencies within the project corridor l Identified potential bottleneck areas l Integration modeling achieved its purpose

Lessons Learned l 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 l Identify study area carefully for: »Boundaries »Network details (no. of links & intersections)

Lessons Learned - Continued l Assess potential interface with other tools (e.g., regional model databases, network editing, etc.) l Trip matrices need to go through an adjustment process reflecting actual counts l Assess data needs carefully l Micro simulation model is data hungry & time consuming