An item that should be obtained as quickly as possible in an accident case – especially one involving death or serious injury – is the event data recorder (EDR). These devices can store data including engine speed, vehicle speed, airbag deployment, seatbelt use, and the state of the brakes before and during a crash. While these devices have aided insurance adjusters and researchers, they have also served as electronic witnesses that have sent drivers to jail. By the mid-1990’s when all automobiles had an airbag, microprocessors, solid state memory, and in-car networks gave designers all the tools they needed for capturing system performance and driver reaction data during a crash. One of GM’s early data recorders was responsible for the recall of more than 850,000 Chevrolet Cavaliers and Pontiac Sunfires for inadvertent airbag deployment. The early EDR’s captured data for approximately five seconds before a collision. However, the newer models record data for forty to fifty seconds before impact.
To read this information special equipment is needed, and manufacturers have not adopted the same stance vis-?-vis the ease with which the data from their automobiles may be downloaded. GM, for example, will not share information about a crash event except: (1) With the consent of the vehicle owner or lessee; (2) In response to an official request of police or similar government office; (3) As part of GM’s defense of litigation through the discovery process; (4) As otherwise required by law. Mercedes and BMW have designed their EDR’s so they cannot be deciphered unless the manufacturers cooperate in a particular case.
Documenting driver digressions is the most controversial application of the crash data recorders. A recorder can, for example, reveal if a driver was speeding or braking before an accident. Although it is generally agreed that the recorded information belongs to the vehicle owner, that does not mean it can always be easily concealed. Many motorists do not even know that their vehicles have the recorders and that disclosure of information from the recorder may be an invasion of privacy. Nevertheless, insurance companies and lawyers have frequently been successful in their attempts to obtain court orders to extract data after an accident. One of the most popular pieces of information is the crash pulse information from the onboard accelerometers that activate airbags. Information about this change in velocity and direction of force may indicate the cause of the crash or the severity of injuries.
Vetronix Corporation was one of the first vendors to offer a CDR (crash data retrieval) system that downloaded pre-crash and crash data from the air bag module of most GM and Ford models to a laptop computer. This CDR system included hardware and Windows based software to present crash data in graphs and tables. Depending on the make and model of the vehicle, the CDR program retrieved vehicle speed, engine speed, brake status, throttle position, seatbelt usage, whether the passenger side airbag was enabled, and other data. Bosch offered a competitive product and acquired Vetronix several years ago.
The attorney should exert every effort to ensure that the client’s vehicle is secure. The data may be lost due to an inadvertent police “error” such as starting the car, connecting it to a power source, or improperly downloading the data. Any of these events can “erase” the EDR’s memory, and with that erasure may go your chances for an acquittal. The data may be downloaded from one of three points on a large number of models, including the DLC (data link connector or direct link connector) plug under the dash, the airbag control module, or the PCM (primary control module). Although the “black box” can be removed without necessarily damaging the instrument, most engineers see no need for removal and perform their downloads with the EDR still in the automobile.
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