Travel Demand Modeling

Traffic on the roads results from individuals deciding where, when, and how to travel. Decisions such as where to live, work, and shop also impact travel behavior. A travel demand model is a set of mathematical procedures and equations that represent the variety of transportation choices people make, and how those choices result in trips on the transportation network.

TRPC maintains two types of travel demand models for Thurston County. The models have a base year of 2018, and a future year of 2045.

Regional Model Extent
  1. Regional Model
  2. Dynamic Traffic Assignment Model

Regional Model

The regional model is a traditional 4-step model developed in the EMME platform. The four steps are:

  • How many trips and for what purpose do each household produce?
  • What are their destination choices?
  • What mode of travel do they use for each trip?
  • What is the route they take for each trip?

The regional model includes all of Thurston, Grays Harbor, and Lewis counties, and parts of Pierce and Mason Counties. TRPC and its partners use the regional model to identify and implement a coordinated transportation vision across jurisdiction boundaries. The model is ideal for studying:

  • Major transportation investment studies
  • Regional land use and transportation policies
  • Traffic impact studies
  • Travel demand management and commute trip reduction strategies
  • Air quality analyses

Modeling Services

TRPC provides a range of modeling services for our members, their consultants, and non-members. Services range from a simple data requests for traffic counts or volumes to building subarea models.

  • Members may receive most custom data requests free as a membership service. Large requests, such as building a subarea model, are arranged and paid for under separate contracts.
  • Non-members may need to reimburse TRPC for the costs of custom data preparation, unless the request is being made on behalf of a member.

Request Travel Demand Model Services

Download, fill out, and submit the Travel Demand Model Service Request Form (PDF) to or print and fax to (360) 956-7815.

Typical Model Data Requests

  • Traffic counts or traffic volumes (generally no charge)
  • Model file transfer (no charge for members or entities working for members)
  • Zone Distribution (for non-members, a two-hour fee is generally charged, contact TRPC for the rate)
  • Select Link analysis (for non-members, a two-hour fee is generally charged)

Custom Model Services

  • Model development (for members or entities working for members only). Arranged and paid for under a separate contract.
  • Model analysis, future conditions or development scenarios (for members or entities working for members only). Arranged and paid for under a separate contract.
Firms developing proposals to support our members may contact TRPC staff to discuss our custom model services.

Contact Us

  1. Aaron Grimes
    Senior Transportation Modeler

    Thurston Regional Planning Council
    2411 Chandler Court SW
    Olympia, WA 98502
    Ph: 360-956-7575