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.
- Buses with active CAWS experienced 71.55 percent fewer forward collision warnings per 1000 miles than the baseline buses
- Buses with active CAWS also yielded 43.32 percent fewer pedestrian collision warnings.
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