SPONSOR: Oregon Department of Transportation, OTREC

BUDGET: $60,000

ABSTRACT: Portland State University recently conducted a study to investigate the accuracy of the current algorithm used by the Advanced Traffic Management System (ATMS) for calculating and displaying travel time on variable message signs (VMS) in the Portland metropolitan area. This algorithm is referred to as the ODOT Midpoint algorithm. The results of the project revealed that the algorithm performed reasonably well, and provided the level of detail necessary for VMS applications under normal traffic conditions. However, under periods of congested traffic, the algorithm appeared to underestimate travel times. Since the conclusion of the project, PSU has continued further investigation into alternative algorithms that may perform better under congested conditions, specifically the Coifman algorithm. This project intends to build upon the results of both research efforts to determine the best approach for improving travel time estimates that can fully support real-time applications. These applications include providing travel time estimates on VMS, TripCheck.com, and the 511 traveler information system. At the conclusion of the project, it is desired that a methodology can be recommended that will provide accurate measures of travel time, and that can be used across all three applications. The project will be spearheaded by the Portland State University, under the direction of Dr. Kristin Tufte, the designated Principal Investigator. The ODOT project manager will be Hau Hagedorn. Deliverables have been identified for every task to ensure that the project shows progress and to provide documentation throughout the life of the project. The work deliverables will be approved by ODOT.

PRODUCTS:

journal Kothuri, S., Tufte, K., Fayed, E., and Bertini, R.L., "Toward Understanding and Reducing Errors in Real-Time Estimation of Travel Times." Transportation Research Record: Journal of the Transportation Research Board, Transportation Research Board of the National Academies, Washington, D.C., 2008. (In Press).

report Tufte, Kristin, and Kothuri, Sirisha, "Assessment and Refinement of Real-Time Travel Time Algorithms for Use in Practice - OTREC Phase I - Final Report."

report Tufte, Kristin, and Kothuri, Sirisha, "Assessment and Refinement of Real-Time Travel Time Algorithms for Use in Practice - Final Report."