Method to Determine Vehicle Speed During ABS Brake Events Using Heavy Vehicle Event Data Recorder Speed 2010-01-0999

Many heavy vehicles have an event data recorder (EDR) that can record pre-event and post-event information. It has been previously reported by researchers that the EDR speed is under-reported during hard braking. Reust (2004) and Reust and Morgan (2006) . Well documented tests were conducted with instrumented vehicles to measure time, speed and distance. The vehicles used for this study were equipped with engines manufactured by the Detroit Diesel Corporation. The tests also include measurement of individual wheel speeds and corresponding wheel slip. The authors offer a method to better determine true vehicle speed of a heavy vehicle with air brakes during ABS braking events by using specific speed data from the EDR. The results show that the trend of the EDR-reported speed can be used to determine a precise time of when brake initiation first began. The results of the vehicle speed and brake initiation can be used to calculate travel distance during the brake event.