Most modern passenger vehicles contain some form of Event Data Recorder (EDR). The EDR is typically found in the airbag control module, although it can be found in the powertrain module on some vehicles. These devices record vehicle and occupant information for a brief period of time leading up to and during a crash. This information can be very useful in the reconstruction of vehicular crashes. Crash Response staff has the capability to retrieve the data from the modules and the training and knowledge required to analyze and interpret it.
When a crash occurs, the sensors measure the acceleration pulse to determine whether there is enough severity to deploy the airbags. If the airbags do deploy, crash severity (Delta-V) information will be recorded and there may be additional information. Sometimes data will be recorded even if the Airbag Control Module (ACM) just “woke up” but did not deploy the airbags; this is called a non-deployment event. The amount and type of data recorded in either a deployment or non-deployment event varies with the manufacturer and the model of the vehicle.
Recorded event data may include:
- Vehicle speed
- Change in velocity (Delta-V)
- Brake application
- ABS activity
- Seatbelt usage
- Throttle percentage
- Engine RPM
- Gear selection
- Steering angle
- Stability control (engaged / not engaged)