"The National Highway Traffic Safety Administration has passed a regulation requiring car makers to inform customers when their car has been equipped with an Event Data Recorder, the agency said Monday.

EDRs, similar to "black boxes" used in commercial airliners, record data about what a car is doing in the moments just before and after a crash. They do not record the voices of occupants but they do record things like steering wheel movement, how hard the brakes are being pressed and the actual movement of the car itself.

Some privacy advocates have expressed concern that the data, which can be used as evidence in court cases, is being collected without the knowledge of vehicle owners and drivers."