Citation

Muir B. Collision 2008; 3(1): 88-92.

Copyright

(Copyright © 2008, Collision Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Accident reconstructionists have the ability to look at the stored crash data and use what is defined as internal data to calculate and compare against stored crash data that is defined as external data. Internal data is that which is sensed and recorded internally to the airbag control module (ACM) while external data is that which is recorded by the ACM but comes from an external source. This paper compares different sources of crash data retrieval data from two real-world crashes. In the first case, a stationary Pontiac Grand Am was struck from behind by a Chevrolet pickup truck on a highway with a posted speed limit of 60 mph. In the second case, a Ford police vehicle was struck from behind by another Ford police vehicle in a parking lot. When comparing the Ford powertrain control module (PCM) recorded speeds and apparent speed change, the sampling window must be considered when establishing an impact speed. Given that there can be some delay between the PCM sending and the Ford restraint control module receiving the restraint deployment signal (RDS), it would appear that this collision occurred after the -.2 second sample was recorded but before the RDS was received. There was very good agreement between the recorded pre-RDS speed and the closing speed analysis. A clearer view of the events leading up to the collision and the speeds involved can be obtained using the higher resolution of the PCM pre-RDS data when analyzed with the delta-v.