Comparing Event Data Recorder Data (EDR) in Front/Rear Collisions from the Crash Investigation Sampling System (CISS) Database

The accuracy of collision severity data recorded by event data recorders (EDRs) has been previously measured primarily using barrier impact data from compliance tests and experimental low-speed impacts. There has been less study of the accuracy of EDR-based collision severity data in real-world, vehicle-to-vehicle collisions. Here we used 189 real-world front-into-rear collisions from the Crash Investigating Sampling System (CISS) database where the EDR from both vehicles recorded a severity to examine the accuracy of the EDR-reported speed changes. We calculated relative error between the EDR-reported speed change of each vehicle and a speed change predicted for that same vehicle using the EDR-reported speed change of the other vehicle and conservation of momentum. We also examined the effect of vehicle-type, mass ratio, and pre-impact braking on the relative error in the speed changes. Overall, we found that the common practice of using the bullet vehicle’s EDR-reported speed change to estimate the target vehicle’s speed change is reliable and can be adjusted for some vehicle types and mass ratios to improve the accuracy of the target vehicle’s estimated speed change. We also found that about 10-13% of EDR-reported speed changes may have errors larger than ±10%.