In San Antonio, a modeling study found that if traffic congestion were to increase by 25 percent, posting nearby railroad crossing closing delays on freeway dynamic message signs would reduce total network delay by up to 6.7 percent.
Date Posted

Advanced Warning for Railroad Delays in San Antonio, Lessons Learned from the Metropolitan Model Deployment Initiative

Summary Information

This project deployed acoustic and Doppler radar sensors on railroad tracts to detect the presence, speed, and length of trains as they approached highway grade crossings. Sensor data was transmitted to the TransGuide Control Center where computer programs calculated and predicted the time and duration grade crossings at or near freeway exits would be blocked. This information was posted on freeway dynamic message signs to warn exiting drivers of possible delays.

The system was found to work well; however, at the time of the study low levels of congestion in the network did not warrant the implementation of an advanced warning system to avoid long delays. Simulation techniques were used to show the potential benefits of the system and to identify a decision-point at which congestion levels would warrant such a system in the future.


With a 25 percent increase in congestion and a 15 percent driver compliance rate, the simulation model indicated the warning system would yield positive benefits in terms of reducing total network delay. With a 20 percent driver compliance rate the total network delay would decrease by 6.7 percent.

See also:

Science Applications International Corporation. San Antonio's Medical Center Corridor: Lessons Learned from the Metropolitan Model Deployment Initiative. U.S. Department of Transportation. Washington, DC: 2000.

Metropolitan Model Deployment Initiative: San Antonio Evaluation Report (Final Draft), May 2000.

Science Applications International Corporation. Evaluation of the San Antonio Metropolitan Deployment Initiative.
7th Annual World Congress Conference CD; Turin, Italy. November 2000.

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