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EDR - "The Black Box"

March 23, 2017

In the insurance community, the term “black box” has been commonly used to refer to a vehicle’s Event Data Recorder (EDR). The EDR is a recording device found in some vehicles, which records information about a vehicle in the moments before, during, and after a crash. The type of information gathered, and its usefulness in collision reconstruction, remains a mystery for some. Here are our answers to some common black box questions.

Do all vehicles have an EDR?
No. EDRs are not found as stand-alone devices in vehicles. They are integrated as part of other control modules on vehicles. There are various types of control modules in vehicles, all with different functions, but these did not become standard in most vehicles until the early 1990’s. All modern vehicles equipped with air bags will have some form of control module and a large portion of these will have an EDR that can record information.

Can the information from any EDR be downloaded?
No. Although there are hundreds of models of vehicles with air bag control modules, the EDRs on most vehicles cannot be accessed because the manufacturers have not released the information required for a company to build an appropriate data collection tool. Currently, only three major automobile manufacturers have released publicly available hardware and software to download and interpret data – Ford, General Motors and Chrysler. There are also a few select vehicle models from Isuzu, Suzuki, and Mitsubishi that are also publicly accessible.

What kind of information can you retrieve from an EDR?
The type of information that is recorded varies from model to model and amongst manufacturers. The common information that is stored includes pre-event vehicle speed, throttle position, engine RPM and brake switch status. Also, for the duration of the crash pulse, acceleration and change in velocity data is commonly reported. Other vehicle parameters include driver and front passenger seat belt buckle status, ignition cycles at time of event and download, fore/aft seat position, air bag and pre-tensioner firing times, cruise control status, ABS activation, and timing of related events. EDR data may not always be present after an event since damage to the vehicle’s electrical system can prevent recording of information.

Is EDR data reliable for understanding how and why a collision occurred?
Yes, and No. EDR data can be extremely useful in understanding collision circumstances. However, there are instances when EDR data is not consistent with the physical data and can be proven to be inaccurate. Trained collision reconstructionists should be retained to properly interpret the data in conjunction with a review of the physical evidence and consideration of human factors.

What changes are going to occur with EDRs in the future?
The National Highway Traffic Safety Administration (NHTSA) is Transport Canada’s sister organization in the U.S. Last year, NHTSA mandated that by September 2012 all new vehicles manufactured in the U.S. must have a commercially available tool for accessing and downloading data from the air bag control modules. This means that in the next few years, more and more vehicles will have accessible modules.To obtain a current list of vehicles that are equipped with downloadable EDRs, please contact Sintra Engineering.


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