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Black Box Data Used in Car Accident Cases

March 15, 2022Car Accidents

In some St. Louis car accident cases, a driver knows they were not at fault but can’t prove it due to a lack of witnesses or video evidence. Often both drivers claim that the other was at fault, so without much evidence, it can be difficult to prove your case.

At Goldblatt + Singer, the St. Louis Injury Law firm, we always assign a team of investigators to seek out witnesses, doorbell or traffic camera videos, or any other evidence available to support your case. Sometimes this means that we look at your car’s black box data.

What is a Black Box, or Event Data Recorder (EDR)?

This small device, typically found in newer vehicles, collects and saves data about the car’s physical condition and even the driver’s behavior before and during an accident. The National Highway Traffic Safety Administration (NHTSA) has been collecting data from black boxes since the early 2000s to understand how accidents happen and hopefully prevent them. The car’s manufacturer also uses this data to improve safety in future car models. But in many car accident cases, the data contained in this box also helps to reconstruct what happened and build your case.

If you drive an older model or classic car that was made in the previous century, it most likely doesn’t have a black box (although a few brands started using them as early as 1994). If you’re unsure if your car has a black box, your lawyer can look up this information for the model, make, and year. If your car doesn’t have one, we may be able to gather evidence in other ways. As time passes, the possibility of retrieving external data such as traffic camera or doorbell camera video is reduced, so the sooner you speak with a St. Louis car accident lawyer, the better.

What Data Does a Black Box Contain?

Most black boxes store about 30 days of data before the information is overwritten as needed. In many cases, data pertaining to the time before, during, and after the crash are important evidence in a car accident case. Not all black boxes are the same – some track more data than others. Here are some items that your black box may record:

  • The average speed of your vehicle in the past 30 days and/or on the trip where the accident occurred
  • How often the vehicle was driven over a speed limit
  • The highest rate of speed during the trip
  • Daily or monthly engine use
  • Whether the clutch was engaged (if your car has a clutch)
  • If and when the vehicle suddenly decelerated
  • Brake switch status (if the driver braked, and sometimes exactly when)
  • Load factor
  • Following distance
  • The force of impact at the time of the crash
  • How fast your airbag deployed
  • Whether a seatbelt was in use at the time of the crash
  • Seat positions
  • Maintenance issues (if the car had needed maintenance for some time)
  • Current throttle position (%)
  • Steering angles
  • The tilt of the vehicle
  • Engine oil pressure
  • Tire pressure
  • The number of collisions the vehicle has been involved in previously

Who Can Access This Black Box Data and Why?

Understandably, some people are not thrilled to learn just how much data their own car is collecting. In 2015, Congress passed the Driver Privacy Act, which states that EDR data is the property of the vehicle’s owner or lessee, and that this data cannot be retrieved without the owner’s knowledge and consent. There are a few exceptions:

  • A court can authorize release of the black box data if it’s deemed necessary for a court proceeding. For example, if it becomes necessary to file a lawsuit to seek compensation for your car accident damages, we might ask the court for data from the other driver’s car.
  • The owner or lessee of the car often consents to have the data accessed for diagnosis or repair work on the car. For example, if your “check engine” light comes on and you take the car to a mechanic, they may access the data to determine what the problem is.
  • The National Transportation Safety Board or DOT may access this information as part of an investigation to learn more about accident causes.
    Black box data can be used by emergency responders in order to provide assistance after a car accident.
  • The data may be used for traffic safety research done by NHTSA or a similar organization, and in this case, any personal data about the owner or lessee is removed.

Some states have created their own legislation adding more restrictions on how black box data is used, but Missouri is not currently one of them.

How Can Black Box Data Be Used as Evidence in a Car Accident Case in Missouri?


In some situations, the EDR data may be evidence of one driver’s liability if it shows that their negligent actions contributed to the collision. Here are some examples:

One or More Drivers at Fault

First, a brief explanation of Missouri’s pure comparative fault laws:

  • It is possible for both drivers to make mistakes that contribute to an accident.
  • In the event that a car accident case goes to trial in Missouri, a jury will be tasked with determining a percentage of fault for each driver.
  • If you are 20 percent at fault and the other driver is 80 percent at fault, you will be responsible for 20 percent of their damages, and they will be responsible for 80 percent of yours. So if you each had $10,000 in damages, they would owe you $8,000, and you would owe them $2,000, making your actual recovery $6,000.
  • Most car accident lawsuits are settled out of court, but the insurance adjuster’s opinion of both drivers’ level of fault will still affect negotiations. For example, if the insurance adjuster thinks a jury will find you mostly at fault, they may not be very motivated to reach a fair settlement. But if we can present evidence that the other driver was all or mostly at fault, they may want to avoid a court case and make a reasonable settlement.

Now you should be able to see why black box data could affect your car accident settlement. Here are some specific ways EDR data could show that a driver was at fault:

  • The data shows the driver didn’t hit the brakes before the crash. This often indicates that the driver was distracted – for example, they may have been looking at their phone or fiddling with the radio instead of watching the road.
  • The recorded speed was significantly over the speed limit. This could indicate the driver was being reckless.
  • The engine was “overactive.” This one is a little less obvious, but an overactive engine could mean that the driver hadn’t taken a break in a long time and was too tired to be driving. In fact, a AAA study found that driving while tired or drowsy could be just as dangerous as driving drunk.
  • Tire pressure was low and wasn’t addressed. If the tire pressure had been low for some time, the driver would have been aware due to a light on the dashboard. If they chose to ignore it instead of checking the tire pressure, and a tire blew out, leading to the crash, the driver might have been negligent in not maintaining their vehicle.

An Employer

Although we think of accidents as being the fault of at least one driver, this isn’t always the case. Sometimes the actions of third parties can contribute to or cause a collision. If one motorist was driving a company vehicle, it’s possible the accident occurred because the vehicle had not been maintained properly. If so, there may be evidence in the EDR data of the vehicle’s long-standing need for maintenance. Unlike in the above tire pressure example, the vehicle and responsibility for its maintenance would probably belong to the employer, making them liable instead of the driver.

Parts Manufacturer

Another potential cause of an accident is a sudden failure of a car’s engine or components despite receiving regular maintenance. Faulty brakes, for example, can cause a very bad accident. A problem with engine timing might lead to a vehicle unexpectedly stalling at a bad time. Careful study of the black box data may show that a product defect, not a driver, led to the crash. In this case, the car manufacturer or component producer may be liable for the accident.

Call Goldblatt + Singer Car Accident Attorneys in St. Louis

The above are only a few examples of how black box information may be used as solid evidence in your car accident claim. There are other kinds of evidence, and we will work to build the strongest case possible to get you all the compensation you deserve. If you or a loved one were hurt in a car accident, we recommend you speak to a St. Louis Car Accident Lawyer at Goldblatt + Singer, the St. Louis Injury Law Firm, as soon as possible to assist you in preserving this critical data by calling 314-888-1000.

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