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Accuracy of Event Data Recorder in 2010 Ford Flex During Steady State and Braking Conditions

NCJ Number
International Journal of Passenger Cars-Mechanical Systems Volume: 4 Issue: 1 Dated: 2011 Pages: 677-699
Date Published
23 pages

This study tested the accuracy of the Restraint Control Module (RCM) Event Data Recorder (EDR) on a 2010 Ford Flex during both straight line steady state and maximum ABS braking. 


Six runs were made starting from 48 kph (30 mph), six runs starting from 80 kph (50 mph), and six runs starting from 113 kph (70 mph). Nondeployment events were artificially induced after a period of steady state driving followed by maximum braking for the last 2.5 seconds prior to creating the event, which was intended to simulate braking just prior to a crash. Following each run, data were collected from the RCM EDR using the Bosch Crash Data Retrieval system. A Racelogic VBOX SL3 20 Hz differential GPS speed data recorder also served as a data acquisition system for vehicle CAN bus speed, accelerator position, RPM, and brake tape switch data. Graphs of RCM speed/brake/accel pedal data compared with VBOX speed and other data over time are presented. The differences between RCM and VBOX speed were plotted and fitted to linear model, using the method of least squares. Under steady state conditions, the RCM EDR average under-reporting error was 1.4 percent at 113 kph (70 mph), and the 99-percent confidence interval was within 2.5 percent at 113 kph (70 mph). During hard braking, the EDR under-reports an average of 3 kph (1.9 mph) compared to VBOX GPS, with a worst case of 6.8 kph (4.2 mph) at approximately 60 kph (37.2 mph), due to the expected wheel slip during hard braking. (publisher abstract modified)

Date Published: January 1, 2011