Evaluation/Report for Collision Avoidance & Mitigation System (CAMS) on Winter Maintenance Trucks (WMT)
|Keywords:||Collision avoidance and mitigation systems, winter maintenance operation, driver behavioral analysis, encroachment rate, response time, relative headway, safety improvement, warning light.|
Snow removal and deicing activities are commonly performed by roadway agencies to enhance winter mobility and safety. Due to slower travel speeds during these operations, combined with low visibility and reduced pavement friction, the potential for rearend collisions with winter maintenance trucks remains a persistent issue. A prototype collision avoidance and mitigation system (CAMS) was recently developed by a private vendor and was mounted on the rear of winter maintenance trucks (WMT) in southeast Michigan during the 2017-2018 winter season. The CAMS system includes a rear-facing radar, camera, and warning light bar, in addition to a cleaning/washing system, computer hardware, and an in-cabin display. Research was performed to evaluate the effectiveness of this prototype CAMS in consideration of potential broad implementation throughout the state of Michigan. Two MDOT CAMS-equipped winter maintenance trucks were utilized during plowing activities in early 2018 to evaluate both the operational performance of CAMS and the extent to which CAMS improves drivers’ behavior when encroaching the rear of the truck. The study also investigated the potential of CAMS to reduce WMT-involved crashes along with the economic viability of widespread implementation of CAMS across Michigan. Although the CAMS showed potential for positive benefits on driver behavior, in terms of reaction time and encroachments to the rear of the WMT, several operational and performance issues were identified, both during field operation and from operator feedback, that require further investigation and remediation before the system can be recommended for widespread implementation. Specific issues included: 1.) persistent occlusion/blockage of the radar/camera housing unit by debris caused by inadequate performance of the cleaning system and 2.) inconsistent/imprecise activation of the CAMS warning light, which included false activations from vehicles in adjacent lanes and missed or delayed activations for vehicles encroaching within the warning zone behind the WMT. Several recommendations for improvement of the CAMS system were provided herein, and subsequent evaluation is necessary prior to broad implementation across Michigan.