“Black Boxes” in Your Car Can Help in Accident Reconstruction


When a plane crashes, officials scramble to find the “black box” data recorder that will give them information about the crucial moments immediately before the accident. But black boxes may record data in cars as well as airplanes. There’s a good chance your car has one. If you’re involved in an auto accident, the tool can be used to bolster any resulting injury claims.

Black boxes are officially known as electronic data recorders or EDRs. They are in the majority of new model cars and record a vast amount of data from your vehicle. The data may be used to determine what was happening in the seconds preceding and following an accident. They can reveal the difference between a motor vehicle defect and a driver’s error.

What do EDRs do?

Like the tools auto mechanics use to diagnose engine problems, accident reconstructionists can use EDRs to diagnose accidents. These black boxes record a variety of information as you operate your vehicle, according to the IIHS. Among the items recorded are:

  • Change in forward crash speed
  • Travel speeds
  • Engine throttle percentages (how far the gas pedal was pushed)
  • Whether or not the brake was applied
  • Whether or not the driver was wearing a seat belt
  • Number of impacts
  • Time between impacts
  • Airbag deployment details
  • Ignition cycles
  • Changes in speed
  • and more…

But the EDRs have shortcomings. The data may not survive a crash. If the black box is damaged, the data within may be irretrievable. Also, the information isn’t 100% accurate 100% of the time.

USA Today reported in 2010 (in the wake of massive Toyota recalls) that EDRs rely on the same electronics in a vehicle that may have caused the accident in the first place. If the accident is caused by an automotive defect, the data can be misleading.

Initially a safety measure, not an investigative tool

EDRs were initially created to help keep people safe, not to be used for post-accident investigations. But with their growing use and complexities, their usefulness for insurance companies and car accident victims has grown.

Dave Wells of the King County Sheriff’s Office in Washington says that these black boxes were first used to test safety systems. According to NPR.com, they allowed safety engineers to test their systems in real-world scenarios. However, using them in accident reconstruction was a natural progression.

In retrieving black box data, time is of the essence

Generally, EDRs record data at certain times and even make permanent imprints when airbags are deployed. But if the unit has to be removed during repairs or is damaged itself, all of the data within can be easily lost.

According to the American Bar Association, the boxes can also record accident information when airbags are not deployed, though the EDRs will only store this information through a set number of engine-ignition cycles. Waiting too long to retrieve the data, therefore, could leave you with nothing to retrieve at all.

Proving who is at fault in an auto accident is crucial in determining who has financial responsibility for the damage to your vehicle and your physical injuries. While black boxes can help, they are far from the only tool at our disposal for accident reconstruction.