What is an Event Data Recorder?

Event Data Recorders are a highly useful tool in accident reconstruction.

Published June 2, 2022

Automobile manufacturers have been placing “black box” Event Data Recorders (EDR) in vehicles since the early 1990s. Because this technology has been adopted by nearly all auto manufacturers, it is highly likely that today’s accidents involve one or more vehicles equipped with EDR.

Most people are familiar with the term “black box” due to its use by the media in relation to airplane crashes. These are Flight Data Recorders and are an actual unit (though not black) designed to record up to 25 hours of flight data associated with a crash. Vehicles have Event Data Recorders, which are not as straightforward.

As defined by the National Highway Traffic Safety Administration, EDRs are, “devices 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 a crash.”

EDRs are a highly useful tool in accident reconstruction. Through the proper interpretation of the data, experts can determine key factors of the accident and assist attorneys, insurance, or law enforcement with understanding the facts of a case.

So, what does an EDR record?

If functioning properly, an EDR can record a lot of information:

  • Accelerations
  • Changes in velocity
  • Vehicle speed
  • Engine speed
  • Percent throttle
  • Accelerator pedal position
  • Braking
  • Steering wheel angle
  • Cruise control status
  • Yaw rate
  • Vehicle dynamics
  • Warning lights
  • Outside temperature
  • Transmission range
  • Traction control activity
  • Roll angle
  • ABS activity
  • Seatbelt usage
  • Seat position
  • System deployments (such as air bags) and their timing
  • Headlight status
  • Tire pressure
  • Passenger status
  • Door status
  • Diagnostic Trouble Codes


Specialized equipment and software are required to download the data from EDRs and are specific to the make and model of the vehicle. Currently, our accident reconstruction experts can download data from 70 makes and 760 models of vehicles, including cars, trucks and commercial vehicles. View the list here.

Please feel free to contact us for EDR downloading and interpretation, or just if you would like an expert to advise on the proper method of preserving the data.

Insurance adjusters, learn how EDR downloads specifically help in accident claim disputes here.