Vehicle “Black Box” Data in Motor Vehicle Collision Cases

Our work in automobile accident lawsuits has been made more complex, and to some extent more subject to accurate proof, by the proliferation of “black boxes” recording computer data of some sort in virtually every late model vehicle on the road.

Most people have heard that after plane crashes, investigators look for the “black box” data recorder of the plane to figure out what caused the crash. What many drivers fail to realize is that cars and trucks also records significant amounts of data that can either help or hurt them in their personal injury case. Still fewer realize that failure to preserve data after a crash can have devastating effects in a serious personal injury case.

An event data recorder (EDR) or electronic control module (ECM), typically referred to as the “black box”, is a device installed in a motor vehicle to record technical vehicle and occupant information for a brief period of time before, during, and after a crash.

Although this information typically is read for seconds, those seconds worth of data can be vital in winning and losing a case. The information that is gathered from the EDR or ECM may include a vehicle’s speed and acceleration, whether air bags were deployed, if breaks were applied and if seat belts were worn. This information can be downloaded from the EDRs memory to help crash investigators, police, and others understand what happened in the vehicle, how a vehicle’s safety systems performed, and sometimes even responsibility in the crash.

Typically, EDRs are located under the passenger front seat, driver’s seat, or the center console of a vehicle. Different manufacturers use different software, some of which is proprietary and tightly controlled by the manufacturer. It is important to employ an accident reconstructionist who both has and is trained in the specific EDR / ECM system software.

When I attend vehicle inspections, often with the experts for both sides, they downloading data from a microchip onto a laptop computer by connecting a wire to a plug under the car’s dashboard, which will then generate reports for use in accident reconstruction.

There are two primary types of recorded crash events. First, a non-deployment event records data, but does not deploy the air bags—it contains pre-crash and crash data; however, after 250 ignition cycles, the data is wiped out. Second, in a deployment event, the air bags are deployed. The recorded data includes pre-crash and crash data, which is saved and may never be overridden.

More sophisticated modules, such as on newer large trucks, records a variety of other operational data.

The National Highway Traffic Safety Administration (NHTSA) proposed rules last December that would make it mandatory for all light vehicles manufactured after September 1, 2014 to have event data recorders (EDRs) installed. Light vehicles include passenger cars, multipurpose passenger vehicles, trucks, and buses with a gross vehicle weight of 8,500 pounds or less. These new regulations could make it easier for investigators to figure out important information that led up to the event.

The NHTSA  released a statement on their website saying “EDRs can have a major impact on highway safety, assisting in real-world data collection to better define the auto safety problem, aiding in law enforcement, and understanding the specific aspects of a crash.”

EDR data can serve as powerful evidence in motor vehicle crash cases where liability is in question. However, an EDR cannot be used in all crash situations. They are not completely reliable, and may sometimes misread speed, air bag deployment, and seat belt use. In one of our recent cases a tractor trailer t-boned a passenger car, killing both people inside, but nothing of that incident was recorded on the truck’s EDR. In other cases, we have been unable to get data from an EDR that was burned beyond usefulness or had been left in an “off” position by the company.

Either party may challenge the admission of the EDR into evidence for the following reasons:

–        The EDR was not in proper working condition and accurately recording information at the time of the accident;

–        Expert testimony concerning the calibration and/ or maintenance of the vehicle;

–        The EDR data is inconsistent with the damage photos, measurements at the accident scene, and testimony of witnesses.

There is a growing body of case law around the country that counsel must carefully evaluate regarding the admissibility of EDR data. Looking at the case law, lawyers seeking to use EDR data must be vigilant about laying a foundation and chain of custody for the data retrieved from an EDR, and use an expert who is trained in examining this data.

However, it can be expensive to have this evidence examined by and proceed through an evidentiary hearing for the admission of the data and the proposed expert testimony. If the proper steps are taken, the evidence may be admissible and help ensure the most accurate snapshot of what actually occurred in the vehicle.

Data from an event data recorder may represent the best evidence Objective evidence from the EDR can be more reliable than eyewitnesses and traditional reconstruction as to what occurred in the seconds prior, during, and after a serious collision. However, as always the devil is in the details, and we must always remember that while figures don’t lie, liars figure, so we have to guard against falsification and misinterpretation of EDR data.

Ken Shigley is past president of the State Bar of Georgia (2011-12), double board certified in Civil Trial Advocacy and Civil Pretrial Advocacy by the National Board of Legal Specialty Certification, and lead author of Georgia Law of Torts: Trial Preparation and Practice.  His Atlanta-based civil trial practice is focused on representation of plaintiffs in cases of castastrophic personal injury and wrongful death.


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Photo of Ken Shigley Ken Shigley

Ken Shigley, senior counsel at Johnson & Ward, is a former president of the State Bar of Georgia (2011-12). He was the first Georgia lawyer to earn three board certifications from the National Board of Trial Advocacy (Civil Trial Advocacy, Civil Pretrial Advocacy…

Ken Shigley, senior counsel at Johnson & Ward, is a former president of the State Bar of Georgia (2011-12). He was the first Georgia lawyer to earn three board certifications from the National Board of Trial Advocacy (Civil Trial Advocacy, Civil Pretrial Advocacy, and Truck Accident Law). In 2019, he received the Traditions of Excellence Award for lifetime achievement. Mr. Shigley was the lead author of eleven editions of Georgia Law of Torts: Trial Preparation and Practice (Thomson Reuters, 2010-21). He graduated from Furman University and Emory University Law School, and completed certification courses in trial practice, negotiation and mediation at Harvard Law School.