Everyone knows about electronic flight-data recorders, also known as black boxes. But few people are aware that automakers are installing similar devices in millions of new cars — devices that keep a detailed record of what happens while you’re on the road.

At its convention this past May, the Association of Trial Lawyers of America felt compelled to whip together a tutorial called The Black Box: It’s Not Just in Airplanes Anymore. What did those lawyers learn? General Motors now equips many of its cars with what are called Event Data Recorders, small boxes that fit under the passenger seat and record data like speed, seat-belt use and whether the brakes were depressed in the final five seconds before a crash. (Other car companies are using similar technologies.) The information that’s retrieved has been a bonanza for police departments, insurance agencies and — yes — trial lawyers, but these devices are also raising thorny privacy issues. Can Big Brother use these boxes to keep tabs on our whereabouts? And who really owns the information in the black box that’s in your car, anyway?