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Review of TPB Travel Modeling Procedures

It is generally considered best practice for an MPO to get an external review of its travel demand modeling process on a regular, on-going basis. In 2003, TPB staff chose to conduct a review of the modeling procedures using a panel from the Transportation Research Board (TRB). In more recent years, TPB staff has hired a consultant to provide that review. Both efforts are described below.

Transportation Research Board (TRB) Review

At its April 17, 2002 meeting, the TPB approved a process for conducting a review of the region's travel modeling procedures. The process called for the TPB to engage a respected non-partisan organization, such as the Transportation Research Board (TRB), to appoint the members of the peer review panel and oversee the review process. A request was formally made to the TRB on May 8, 2002 in a letter from then TPB Chair, Phil Mendelson. The TRB accepted this task and began its analysis of the TPB modeling procedure in January 2003. On September 8, 2003 the TRB submitted its first letter report and on May 10, 2004 the TRB concluded its analysis with the submission to TPB of its second and final letter report. TPB staff provided detailed comments on each of the TRB reports in letters of September 8, 2003 and May 13, 2004 respectively.
The following materials document the TRB review and TPB staff comments:

• First letter report from TRB - September 8, 2003
• TPB staff comments on TRB first letter report of TPB models - September 8, 2003
• Descriptions of Proposed Work Elements for the TPB Models Development Program - December 24, 2003
• Appendices to Descriptions of Proposed Work Elements - December 24, 2003 (2 MB)
• Second letter report from TRB - May 10, 2004
• TPB staff comments on TRB second letter report of TPB models - May 13, 2004

Scan of Best Practices in Travel Demand Forecasting

Beginning in FY 2006, the TPB has had a task-order consulting contract to scan the best practices in travel demand forecasting across the U.S.  The scope of work for this project includes three components:

• Attend all meetings of the TPB Travel Forecasting Subcommittee and other committees as appropriate;
• Provide written guidance to the TPB staff on specific models development issues raised at either the Travel Forecasting Subcommittee or other forums, drawing upon knowledge of travel demand modeling practice in other MPOs;
• Conduct research focused on specific modeling issues raised by TPB staff.

For fiscal years 2006-2008, the contract was awarded to Vanasse Hangen Brustlin, Inc. (VHB).  For fiscal years 2009-2011, the contract was awarded to Cambridge Systematics, Inc.  In FY 2012, the contract was awarded to AECOM. The following documents have been produced:

• Vanasse Hangen Brustlin, Inc. (VHB):
• Results of FY 2006 Travel Forecasting Research (September 22, 2006).
• Results of FY 2007 Travel Forecasting Research (November 16, 2007).
• Expanded Evaluation of Peak Spreading (June 30, 2008).
• Estimating the Impact of Exurban Commuters on Travel Demand (June 30, 2008).
• Cambridge Systematics, Inc. (CS):
• Fiscal Year 2009 Task Reports, Final Report (November 20, 2009).
• Fiscal Year 2010 Task Reports, Final Report (November 16, 2010).
• Fiscal Year 2011 Task Reports, Final Report (June 30, 2011).

The reports listed above can also be found on the "AMPO Travel Modeling Work Group" webpage, which also lists similar reports for other MPOs.