When an oncoming train struck a Cadillac at a Georgia railroad crossing, three occupants were killed. The lone survivor filed a $12-million wrongful-death claim against the railway,
but her case was quashed by an unusual "witness." The jury rejected the survivor's suit after hearing evidence downloaded from the car's onboard data recorder, or "black box." The device revealed that the car had stopped on the tracks before it was hit.

This case, decided in 2002, was among the first in which an automobile data recorder played a pivotal role. But it won't be the last: Black boxes, long required in airplanes, are now standard in more than 65 percent of new cars.

General Motors began installing black boxes in the 1970s as part of the airbag system. The devices continuously monitor information such as speed,
G-forces and seat-belt tension to determine when a crash is imminent. But unbeknownst to most drivers, black boxes preserve these details for the seconds preceding an airbag "event." In recent years such data have been cited by prosecutors in criminal trials and by
carmakers in product-liability suits--to show that drivers were speeding, for example, or not wearing seat belts.

The jury is still out on whether drivers "own" their black-box info. Attempts by the feds to require the boxes and standardize their data sets have so far been rebuffed. But last year, recognizing this new potential for privacy invasion, California became the first state to require
a court order to download black-box data without owner consent.