The deployment of side object detection systems on 257 transit buses in two different transit agencies reduced the side collision rate per 100,000 Vehicle Miles Traveled by 0.186.

December 15 2008
Washington,District of Columbia,United States; Salt Lake City,Utah,United States; Cleveland,Ohio,United States

Summary Information

A United States Department of Transportation research initiative on collision warning systems in private and commercial vehicles included a transit vehicle component which deployed side collisions object detection systems (SODS) in transit buses. Side collisions comprise approximately 49% of all transit bus collisions, resulting in significant costs to transit agencies. An independent evaluation estimated the effectiveness of SODS in reducing side collisions and its return on investment for each agency. The evaluation was based on the system costs associated with acquisition, training, maintenance, and the benefits attained from the savings due to the reduction of side collisions as a result of SODS. Not all of the costs were included, specifically fines, costs of having a bus out-of-service while under repair, cost of schedule delays and operational disruptions, and costs of accident investigation.


The evaluation quantified the reduction in the type of side collisions that SODS could prevent. The performance of SODS in identifying side objects was limited to objects located toward the forward side of the bus, and below the side mirrors. Thus, benefits attributable to SODS did not include collisions with objects on the rear side of the bus or near the side mirrors.

The deployment of SODS on 257 transit buses across two agencies reduced the rate of side object collisions relevant to SODS by 0.186 per 100,000 Vehicle Miles Traveled. Considering the costs of acquisition, training and maintenance, this benefit would result in a positive return on investment in 12 years, the average life of a transit bus.

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Side Object Detection System Evaluation: Final Evaluation Report

Author: J. Rephlo, S. Miller, R. Haas, H. Saporta, D. Stock, D. Miller, L. Feast, B. Brown

Published By: USDOT

Source Date: December 15 2008

EDL Number: 14461



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Typical Deployment Locations

Metropolitan Areas


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Benefit ID: 2010-00632