Risk Mitigation Planning for Revenue Service Testing of Bus Automated Emergency Braking

Document Type

Journal Article

Publication Date


Subject Area

place - north america, place - urban, mode - bus, planning - safety/accidents


Bus, Pedestrian Avoidance Safety System (PASS)


In 2017, the Federal Transit Administration awarded Pierce Transit of Lakewood, WA, a $1.66 m grant for a bus collision avoidance and mitigation safety research and demonstration project. The project scope includes installation of an advanced technology package, the Pedestrian Avoidance Safety System (PASS) that uses light detection and ranging (LiDAR) sensors to trigger automated deceleration and braking. Thirty transit buses are being equipped with PASS and will be monitored using telematics to transmit and collect critical test data. The test plan includes collecting data while operating the buses in “stealth mode” with PASS detecting and logging events, but not activating brakes automatically or warning the drivers. At the conclusion of “stealth mode” operation, Pierce Transit will make a go/no-go decision on whether to activate PASS’s automatic deceleration and braking functionality for revenue service with passengers. This paper describes the risk mitigation process developed to determine if the system is safe enough to allow operation in revenue service. The process includes: broad stakeholder engagement, constituting an ad-hoc working group within Pierce Transit to advise executive management, development of decision-making criteria, consultation with state and federal officials on regulatory requirements and compliance, review of applicable standards and engineering test protocols, engineering consultations with the bus original equipment manufacturer, and road testing to simulate revenue service, collect data, and obtain feedback from drivers and maintainers.


Permission to publish the abstract has been given by SAGE, copyright remains with them.