Safety and Operational Assessment of Yield-to-Bus Electronic Warning Signs on Transit Buses

Document Type

Journal Article

Publication Date


Subject Area

mode - bus, place - north america, infrastructure - bus/tram priority, infrastructure - right of way


bus, electronic warning signs, Yield-to-bus (YTB)


Transit buses generally experience difficulties merging into traffic after stopping at off-traffic stops; this situation generates potential hazards for both the bus moving back into traffic and the surrounding vehicles. Several states have implemented yield-to-bus (YTB) laws and programs to help alleviate these hazards. One of the challenges facing YTB initiatives is the lack of quantitative data to justify effectiveness. In this paper, flashing electronic YTB signs that use light-emitting diodes on the back of buses were evaluated as a major effort of the Florida Department of Transportation Transit Office to assess the effectiveness of the YTB program. YTB behavior, safety conflicts, and reentry time were proposed as three performance measures to evaluate the safety and operational impacts of electronic YTB signs. It was found that electronic YTB signs had the potential to improve YTB behavior of motorists behind the bus. In addition, with the electronic YTB signs, the number of safety conflicts was either reduced or was at least no greater than those of the baseline scenario, which consisted of a YTB decal. The reentry time from pullout bays was also improved. Additional recommendations about compliance, installation, and operation of electronic YTB signs are provided.


Permission to publish the abstract has been given by Transportation Research Board, Washington, copyright remains with them.