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Thurston Regional Planning Council (TRPC) Travel Model Peer Review Report

5.0 Topics of Interest to Thurston Regional Planning Council

Prior to the peer review, TRPC issued two Requests for Qualifications (RFQs) for modeling support, one for a model developer and one for a model consultant. TRPC intends for the model developer to co-locate with TRPC staff to carry out a comprehensive update to the region's travel model under the direct management of the TRPC project manager and with the support and advice of the model consultant. The RFQs specify a draft scope for the model update work. That draft work scope, the TRPC application for a TMIP peer review, and materials prepared and presented by TRPC staff to the peers together identify the issues driving the model update and its potential work tasks.

This section of the report blends the materials listed above to set a detailed context for the specific TRPC questions and panel responses following in Sections 6 and 7. The intent here is to organize stated TRPC modeling interests in a framework easily recognizable to a modeler for quick identification of the model and data features on which TRPC planned to focus the most attention. Each subtopic within this section describes the stated TRPC interest and indicates the scope of the peers' response. Actual peer responses follow in Section 6. This section also includes topics about which TRPC did not originally express interest but which the panel concluded deserved attention.

5.1 Overall Modeling Framework

Geographic Extent and External Travel

The highest TRPC model update priority is to appropriately treat travel to and from the PSRC region to the north, especially in the I-5 corridor and for travel to and from Joint Base Lewis-McChord (JBLM). Prior to requesting this peer review TRPC had already concluded that this would entail expanding the geographic coverage internal to its travel demand model with both additional TAZs and additional network details. The question of geographic coverage creates implications for almost every other model update task; the panel spent considerable time discussing and making recommendations on this topic.

Trip Generation

TRPC's original draft scope of work includes coefficient re-calibration "in all stages of the model"[6] plus appropriate general re-calibration and re-validation. The geographic expansion of the model already mentioned will create additional demands upon the trip generation components, their update, and the necessary supporting data. The panel discussion touched in several ways upon these needs.

5.2 Modeling Framework Specific To Transit

5.3 Modeling Framework Specific to Freight

5.4 New and Existing Data Sources

5.5 Integration with Simulation and Dynamic Traffic Assignment (DTA) tools

With its system-management-oriented policies TRPC has a strong interest in analysis capabilities that provide more operational and temporal detail than the demand model. Indeed, the agency has already developed a DTA model for its "Smart Corridors" project involving two bisecting corridors that converge in downtown Olympia. TRPC intends to enhance its DTA capability for a number of reasons including its preference for operational/management strategies and its need to support more locally-driven studies. The panel made a series of recommendations on this topic.

5.6 Other Panel Observations/Recommendations

Section 6 below lists the explicit TRPC questions posed to the panel along with the panel's responses. As is often the case in model peer reviews, though, the draft scope of model update work and accompanying explicit questions do not necessarily cover all points necessary for the panel to make a complete and consistent set of recommendations. Section 6 therefore includes these extra topics under the heading to which they most logically apply and also lists them for quick reference under their own separate heading, 6.6, for easy identification.

5.7 Model Application Discussion

It is worth concluding this section's discussion of TRPC's modeling interests with a brief overview of the applications TRPC intends for its updated model.The panel recommendations were made with the clear understanding that the updated model will be used to:


[6] REQUEST FOR QUALIFICATIONS #2 - TRAVEL DEMAND MODEL CONSULTANT Thurston Regional Planning Council (TRPC) Travel Demand Model Enhancements April, 2012. p. 3.

[7] TRPC Application for a TMIP Peer Review. 2012. p.5.

Updated: 03/28/2014
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