GM moments: your car is spying on you (no joke)

Bill Machrone, technical editor at PC Magazine, reports in the August issue that he received a letter from the founder of Harris Technical Services, wherein he states that ALL General Motors cars and trucks manufactured after 1995
contain another on-board computer that cannot be read by normal diagnostic means.
The Event Data Recorder (EDR) is analogous to a black-box
data recorder found on commercial aircraft.
The comany reported that EDRs record specific data from various vehicle sensors. Things such as vehicle speed throttle position, brake status, driver seat belt status, and much more can be recorded for up to 5 seconds preceding a collision- in 1-second increments. In the event of a collision where the airbags deploy, this data is permanently written in EEPROM in the Service Diagnostic Module. You won't find the EDR on a parts list for the car. Your local dealer probably won't know it's there. You won't find some mysterious box with lots of wires and no explanation. The EDR is a component of the air-bag control module that must be replaced if the car is repaired and the bags are replaced.
EDR data cannot be downloaded using standard diagnostic tools or software; you must have the download module, available only from Vetronix Corp. in Santa Barbara, California.
As one person put it, yes, your car can snitch on you. The data can be downloaded by insurance company representatives, police, accident reconstrctionists, or rental fleet owners (if one of their cars is involved in an accident; they can obtain data from ALL pertinent vehicles, not only their own, but yours, too, if it is a General Motors make).
For example, the download could report that you were going 38 mph in a 30 mph zone 4 seconds before impact. At 3 seconds you let off on the throttle by 18%, at 2 seconds you applied the brakes, and you were going X mph in impact. And, oh yes, you were not wearing a seat-belt, branding you as careless or negligent at the very minimum."

You can see more on EDRs at the link below.