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Load factor design, Bridges -- Design and construction, Bridges -- Safety -- Evaluation, Sheet piling, Oregon. Department of Transportation


The Federal Highway Administration (FHWA) has put a high priority on the use of existing dynamic message signs (DMS) to provide travel time estimates to the public. The Oregon Department of Transportation (ODOT) has three DMS in the Portland metropolitan area configured to display travel time information. In the near future, ODOT would like to make travel time estimates available on additional DMS, over the Internet on and via 511. Travel time estimates are valuable to the traveling public; however, the estimates must be accurate to be useful. The purpose of this study is to extend prior travel time research conducted by Portland State University with additional analysis to provide statistical confidence in travel time estimates and to determine the best travel time estimation approach for ODOT. The initial ODOT-funded phase of this project gathered a large amount of ground truth data and analyzed the performance of the current algorithms and current infrastructure using that data. However, additional work remains to be done. OTREC Phase I of this project will focus on using the existing data to understand the conditions under which travel time estimation algorithms are not accurate. This extension will build on that work to investigate improvements to travel time estimation algorithms and to identify a set of metrics for travel time accuracy and guidelines for when travel time estimates should be provided. At the conclusion of the project, it is desired that a methodology can be recommended that will provide accurate measures of travel time for use with DMS, the Internet and 511 applications.


This is a final report, OTREC-RR-11-13, from the NITC program of TREC at Portland State University, and can be found online at:

The final report for Phase 1 of this research can be found at



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