Anytime a plane crash enters the news, one of the first items investigators look for in the wreckage is the black box. Also known as the flight data recorder and cockpit voice recorder, these boxes, actually orange in color, are able to reveal important information preceding an accident. They can record information such as cockpit conversations and various details about the performance of components on the plane. This information is used to determine the cause of a crash by looking at the events that occurred before it.



Although these black boxes have been used in airplanes for a number of years, many people do not realize that they are being placed in automobiles as well. Their potential is obvious. Often times in automobile accidents, one or more of the driver's involved may have forgotten, either unintentionally or on purpose, what events took place. If two stories conflict, it is a difficult process to determine who is telling the truth. In addition to this, newer cars with anti-lock braking systems make accident reconstruction much more difficult since these cars do not leave skid marks as well as older ones. The presence of a black box in cars involved in a crash takes a lot of the guesswork out of this type of situation.

Since 1992, a number of major automobile manufacturers, including General Motors, Chrysler, and Ford have been using supplemental restraint systems (SRS) that incorporate air bags. One of the key components in these systems is the SDM, or sensing and diagnostic module. This component is used to constantly measure vehicle speed, throttle, brake status, and other data to determine if airbags must be deployed in the event of a crash.

The SDM is constantly monitoring the vehicle, but will only record if one of two types of event occurs, a near deployment event, or a deployment event. In both situations, the data recorded is the last 5 seconds before the accident, and the crash data itself.

A near deployment event is one that causes the SDM to sense that an accident occurred, but indicates that the conditions leading up to the crash were not severe enough to deploy the airbag. An example of this is if the vehicle did not experience sufficient deceleration prior to impact. In a deployment event, the airbag is actually triggered to deploy.

In both cases, an example of the data may look something like this:

-3 50 1280 2 off

These numbers represent the number of seconds before the event, vehicle speed(mph), engine speed(rpm), percent throttle, and the status of the brakes. In this case, 3 seconds before the crash, the vehicle was still traveling at 50mph, and the brakes were not yet fully applied. This information will be supplied for the last 5 seconds preceding the crash. It may not seem like much data to go from, but knowing when or if the throttle was released and if the brakes were applied, as well as vehicle speed, can be very important in a legal situation when determining fault. In addition to this information, other data recorded at the time of impact includes the status of the seat belt, if the passenger airbag was turned on or off, and if the airbag warning light was on or off.

As made obvious by the description above, the use of the SDM in legal situations can be a valuable tool. The data recorded can give any personal injury practitioner a major advantage. Although accident reconstruction and physical evidence such as skid marks will still be used in investigations, the SDM is able to provide support and clarity to the conclusions reached by investigators in these situations.

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