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What is an EDR? Understanding Event Data Recorder Technology

A car that has crashed into a tree.

Chances are, unless you’ve recently been in an accident, you’ve never heard the term EDR. This acronym is short for event data recorder, and it’s helpful to think of it as the automotive equivalent of the black box on an airplane. It’s a device that keeps track of what exactly is going on with your vehicle up to the point where a crash occurs. Most new cars and trucks are equipped with this electronic eye, but not everyone is familiar with how the device works, or why it exists in the first place.

Is This Thing Recording?

Car accidents can be simple fender benders, but they can also be more complex, particularly if they occur as the result of a malfunction with the vehicle itself. This is where the EDR comes in. The word “event” in this acronym is important, because the device itself doesn’t keep constant track of how you are driving, or how your automobile is performing. It merely provides a snapshot of the seconds leading up to and immediately following the crash, or event itself.

What the EDR Seescar crash

The event data recorder in most vehicles takes a snapshot of important accident reconstruction clues, such as: occupant behavior (number of people in the car, who is wearing a seatbelt); driver inputs (steering, accelerator and brake); the position, speed and yaw angle of the automobile; and other details like the deployment of safety systems and passenger protection systems, as well as the force of any impact that might take place. Combined with a diagnostic of the automobile’s systems taken during the same period in time, this offers accident investigators additional information to use when putting together the sequence of events that led to the crash.

NHTSA Effort

Your vehicle has an EDR for two reasons. The first is that the National Highway Traffic Safety Administration (NHTSA) began pushing for the use of event data recorders more than 20 years ago, in order to gather as much accident data as possible to generate guidelines and regulations related to safer vehicles. Automakers also benefit from EDRs, because they can use the data to pinpoint any issues or problems with their automobiles that could have been implicated in the crash. This team effort has led to better protection for those involved in a car accident, as well as improved systems designed to prevent a crash from ever occurring in the first place.

Check out all the relays, sensors and switches available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on your vehicle’s EDR, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

Photo courtesy of Flickr.


Benjamin Hunting View All

Having been bitten by the car bug at a young age, I spent my formative years surrounded by Studebakers at car shows across Quebec and the northeastern United States. Over ten years of racing, restoring, and obsessing over automobiles lead me to balance science writing and automotive journalism full time.  I currently contribute as an editor to several online and print automotive publications, and I also write and consult for the pharmaceutical and medical device industry.

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