An event data recorder (EDR) is a device installed in a motor vehicle to record technical vehicle and occupant information for a brief period of time (seconds, not minutes) before, during and after an accident. An EDR may record:
- Pre-crash vehicle dynamics and system status
- Driver inputs
- Vehicle crash signature
- Rrestraint usage/deployment status
- Post-crash data such as the activation of an automatic collision notification (ACN) system.
EDRs are devices which record information related to an “event” and in this case, the event would pertain to a vehicle accident. Some devices also make an audio or video record, or log data such as hours of service for truck operators. Generally, the primary EDR function for passenger vehicles resides in the Airbag Control Module (ACM), and for commercial vehicle in the Engine Control Module (ECM). Other modules on the vehicle may also contain additional recorded information pertinent to the crash.
Event Data Recorder Extraction and Analysis
Extraction refers to the ability to “image”, “download”, or “retrieve” EDR data. Introtech experts have been using event data recorder data to support its accident investigation/reconstruction services for over 20 years and have the specialized training and certifications for proper extraction and analysis of vehicle EDR data.
Accident reconstruction is the science of analyzing vehicle collisions using applied physics. EDR data cannot stand alone and should only be used as one tool in analyzing an accident. A comprehensive reconstruction typically includes data from the roadway, witnesses, and vehicle. Vehicle EDR data can be valuable but by itself is not a substitute for a proper and thorough crash reconstruction analysis. An accident reconstruction may include any or all of the following:
- Analysis of vehicle movements including vehicle speeds
- Analysis of vehicle impact angles
- Analysis of time-distance relationships of vehicles
- Analysis of vehicle speed change (delta V) during the impact phase of the crash
- Occupant movement within the vehicles during the impact phase and their resultant injury patterns
See how Introtech used EDR data to complete an accident reconstruction in one of our case studies.