Accuracy of Event Data Recorder in 2010 Ford Flex During Steady State and Braking Conditions 2011-01-0812

The accuracy of the Restraint Control Module (RCM) Event Data Recorder (EDR) was tested 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, intended to simulate braking just prior to a crash. Following each run data was 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 versus VBOX speed and other data over time are presented. The differences between RCM and VBOX speed are 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% at 113 kph (70 mph), and the 99% confidence interval was within 2.5% 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.