An automobile Event Data Recorder (EDR) is an electronic recording device that continuously records information about the vehicle in which it is installed. These devices have come to be known as automobile black boxes, a name inspired by the black box devices that are used in aircraft.
A typical EDR records data in a continuous loop, with newer data overwriting older data. These devices rarely record more than thirty seconds of data. The primary purpose of the EDR is to provide information about traffic crash incidents that may be used to improve vehicle and driver safety.
An automobile EDR is nowhere near as sophisticated, secure or reliable as a black box used in aviation, and care must be taken not to overestimate the value of the data that may be recovered from an automobile EDR.
Newer vehicles include EDRs that are subject to federal regulations, and must record at least thirty seconds of data. Vehicles manufactured prior to the federal requirement may record data gathered during a shorter period of time.
Federal regulations now require specific information to be recorded by an EDR. For the most part, older devices do not record all of the information required for recorders in newer vehicles. Any EDR may potentially record information in addition to that required by federal regulations.
Automobile black box data must be retrieved using a data retrieval tool, a device that is expensive to purchase and would be difficult for a typical person to fabricate. Further, particularly on older vehicles, the data can be difficult or impossible to interpret without appropriate software, and newer EDRs require the use of access codes in order to read the data. It is thus rare for vehicle owners to recover their own data, and remains costly to have it extracted and analyzed by a professional.
Most states do not regulate access to automobile black box data, meaning that following an accident the police may be able to obtain the data without a warrant or subpoena.
Approximately fifteen states have passed laws that restrict the availability of data, and set restrictions on who many obtain the data and under what circumstances it will be available. For example, state laws may generally allow for the access of data only pursuant to a subpoena or court order, while also authorizing certain forms of access without explicit permission from the owner, such as for purposes of diagnosis or repair of a problem with the motor vehicle.
Although some people have suggested that black box data might be accessible to hackers, the data recorded is not the sort that would be of interest to hackers, and the data remains very difficult to access.
An EDR simply records information, and cannot be used to take control of the vehicle.