Simulation Analysis of Route Diversion Strategies for Freeway Incident Management

Report No: 95-R11

Published in 1995

About the report:

Freeway incident management has become an important issue in departments of transportation nationwide. With many of the nation's roadways operating very close to capacity under the best of conditions, the need to reduce the impact of incident-related congestion has become critical. One way to achieve this reduction is to improve the management of traffic after an incident has occurred, including the use of traffic diversion strategies. Very often, however, diversion strategies are employed without proper consideration given to the effect of such a strategy on the alternate route, which in many cases is congested prior to the addition of diverted traffic. Careful analysis of diversion strategies, which includes examination of the operational characteristics of both the freeway and alternate routes, can lead to much more efficient and effective strategies. This project establishes a methodology for analyzing diversion strategies using CORSIM, a microscopic simulation model developed by the Federal Highway Administration capable of simultaneously analyzing freeway and arterial roadways. The model process for incident specification and simulation was tested and applied to several case studies. The results of the study show that the model is a valuable tool in analyzing diversion strategies; the critical freeway volume at which diversion becomes advantageous can be determined, as can bottleneck locations on the alternate routes. Signal timing adjustments can be tested and fine-tuned to achieve the ideal maximum flow along the diversion route.

Disclaimer Statement:The contents of this report reflect the views of the author(s), who is responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the Virginia Department of Transportation, the Commonwealth Transportation Board, or the Federal Highway Administration. This report does not constitute a standard, specification, or regulation. Any inclusion of manufacturer names, trade names, or trademarks is for identification purposes only and is not to be considered an endorsement.


  • Catherine A. Cragg, Michael J. Demetsky, Ph.D.

Last updated: December 18, 2023

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