The Rosco/Mobileye Shield+ system is a collision avoidance warning system (CAWS) specifically designed for transit buses. This project involved field testing and evaluation of the CAWS in revenue service over a three-month period. The system provides alerts and warnings to the 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. Alerts and warnings are displayed to the driver by visual indicators located on the windshield and front pillars. Audible warnings are issued when collisions are imminent.
The pilot test met all of the objectives included in the contract. The vendor equipped 38 buses with Shield+ CAWS. Buses equipped with Shield+ systems logged 352,129 miles and 23,798 operating hours during the official pilot data collection period from April 1, 2016 through June 30, 2016. No Shield+ equipped buses were involved in any collisions with bicyclists or pedestrians. Because Spokane Transit decided to operate its buses in stealth mode, the pilot included the unanticipated benefit of having a control group as well as an active fleet.
The pilot test showed that although driver acceptance was mixed, there were large reductions in near-miss events for CAWS-equipped buses. Consequently, achieving driver acceptance will be a key factor in continued development and deployment of CAWS. As a result of comments received from the drivers, the vendor has begun a program to incorporate desired modifications to the system including reducing false positives. The study also showed that supervisors, drivers and maintenance personnel should be involved in product development, trained in how to use CAWS, and educated in how CAWS can directly benefit them by reducing their risk of collisions.
A second major factor in achieving industry acceptance is to demonstrate the business case for CAWS to both transit agencies and system developers. Transit is a niche market compared with autos and trucks. Consequently it is necessary to demonstrate the profit potential within the transit market to attract developers and capital. Part of this effort should be to stimulate and support the necessary research and development. Although the pilot project produced encouraging results, collisions, injuries and fatalities can be considered “rare events.” A much larger in-service test will be needed to demonstrate actual cost-savings.