Buses equipped with collision avoidance warning systems have potential to reduce insurance claims by 58.5 percent.
Statewide demonstration pilot of a vision-based Collision Avoidance Warning System for transit buses in Washington.
Made Public Date


United States

Active Safety-Collision Warning Pilot in Washington State

Summary Information

This project, conducted under the auspices of the Washington State Transit Insurance Pool (WSTIP), involved field testing and evaluating a vision-based Collision Avoidance Warning System (CAWS) specifically developed for use on transit buses. The CAWS uses four cameras to provide coverage of blind zones where vulnerable road users may be hidden from the driver’s view:

  • a master camera attached to the center of the inside windshield
  • a camera attached to the inside windshield positioned to cover the blind zone on the left front created by the "A" pillar
  • one external forward-facing camera on each side of the bus towards the rear, to cover blind zones behind the driver.

Alerts and warnings about imminent collisions are displayed to the driver by visual indicators located on the windshield and front pillars. The CAWS provides alerts and warnings to a bus driver for the following conditions that could lead to a collision: 1) changing lanes without activating a turn signal (lane departure warning was disabled for this pilot), 2) exceeding posted speed limit, 3) monitoring headway with the vehicle leading the bus, 4) forward vehicle collision warning, and 5) pedestrian or cyclist collision warning in front of, or alongside the bus.


For the demonstration pilot, CAWS were installed on 35 buses at seven WSTIP member agencies including: Ben Franklin Transit, Richland, WA, C-Tran, Vancouver, WA, Community Transit, Everett, WA, InterCity Transit, Olympia, WA, Kitsap Transit, Bremerton, WA, Pierce Transit, Tacoma, WA, Spokane Transit, Spokane, WA, and on an additional 3 buses at King County Metro Transit in Seattle, WA.

Buses in the test fleet were equipped with real-time telematics monitoring. To provide a baseline, CAWS on Spokane Transit buses were set up to collect and transmit data via telematics, but did not issue warnings to drivers. The official pilot data collection period ran from April 1, 2016 through June 30, 2016.

As part of the system's evaluation, 13 years of claims data provided by WSTIP was analyzed and an analysis framework to classify claims according to the magnitude of loss and the relevant explanatory factors was developed to estimate the costs savings of avoided collisions.


  • Applied to the historic costs for claims, the net result was an estimated reduction in vehicular claims of $13.1 million and a reduction in pedestrian claims of $6.9 million. The total reduction of $20.0 million amounted to an estimated 58.5 percent potential reduction in claims due to collisions for all buses insured by WSTIP.

Active Safety-Collision Warning Pilot in Washington State

Active Safety-Collision Warning Pilot in Washington State
Publication Sort Date
Lutin, Jerome; Yinhai Wang; Ruimin Ke; and Steven M. Clancy

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