Crash Data Retrieval / Automotive: Cars, Trucks, SUV and passenger vehicles *
* now including Toyota, Lexus and Scion products as of May 2011
Frequently referred to as Black Box it is neither black nor a box but rather an Electronic Control Module properly referred to as an Event Data Recorder. The Black Box misnomer was first implied for its comparison to Flight Data Recorders which it does not resemble, nor replicate voice data from the cockpit or passenger compartment. It does, however, record pertinent data accumulated in a time frame of up to 5.0 second prior to a Deployment or Non-Deployment event (air bag deployment).
The newer the technology of the automobile the more critical data can be retrieved, e.g. a 2011 Chrysler / Dodge will have enormously more data recorded than a 2000 year model of the same Manufacture.
Some of the data expected to be retrieved or derived from the data retrieved would include: vehicle speed at impact, braking or not braking, accelerating or not accelerating, seat belts in use or not in use, Delta-V (G force of the impact), direction of the impact, steering input, seat belt pre-tensioner (if so equipped) deployed or not deployed, air bags deployed and if so which air bag or air bags deployed and the timing of same.
The SILENT WITNESS: Whereas Crash Data Retrieval is essential in a crash where injuries or deaths occured, it is only one part of the complete investigation and accident reconstruction. To me, it is one of THE most important tools in an accident investigation. an Event Data Recorder does not have the capacity to lie, nor does it have the capacity to record anything other than the data, exactly as it occured. While recovered data is critical it rarely contested. In order to contest the data imaged, there would need to be irrefutable proof that a malfunction or defect of the device itself or a component working in conjunction became undependable. In real life, this rarely happens.
Crash Data Recorders are void of interpretive human errors such as frequently encountered with witnesses and eye witnesses and associated testimony and statements of same. An Event Data Recorder can record only the data and the facts as programmed, e.g. most cases in which a driver insists and testifies he or she was pressing firmly on the brake pedal it is discovered that he or she was pressing firmly on the accelerator pedal or a combination of both.
Most vehicles manufactured after year 2000 and some as far back as 1992, contain a recording device which, with the proper equipment and software, can be read ... or more accurately " imaged ". The amount and quality of the data retrievable is individual to the specific Model Year, Manufacture and type of device installed.
To better understand the definition and function of an Event Data Recorder refer to Wikipedia: http://en.wikipedia.org/wiki/Event_data_recorder