Big Brother has been watching some of us drive for a decade. In another couple years, you'll know if you're under scrutiny. The National Highway Traffic Safety Administration ordered automakers to disclose which cars they sell have black boxes, more formally called event data recorders (EDRs) or electronic on-board recorders, starting with 2011 model-year vehicles.

In 2005, two-thirds of GM and Ford cars had black boxes installed. This is nothing new; PC Magazine columnist Bill Machrone reported fours ago that black boxes were built into passenger cars as early as 1996.

The safety-related reasons are obvious: As younger Americans run out of other things to die from, automobile accidents (including car-bicycle and car-pedestrian) loom large and are in fact the number-one cause of death for people up to the mid-to late 20s. (AIDS and suicide aren't laughing matters, but for the population as a whole, they don't weigh as heavily.) An event data recorder can capture the seconds before, during, and after a crash and report speed, acceleration, whether brakes were on or off, whether seat belts were worn, and airbag deployment.

This information can help researchers understand more about accidents and design safer cars. For instance, researchers would know the actual speed of impact, not just the posted speed limit or eyewitnesses' recollections. Or in a high-speed, single-car accident where there's a question of whether the driver fell asleep at the wheel or perhaps was suicidal, knowing whether the brakes were engaged would be an indicator.

Your Car on the Witness Stand

Event data recorders are "good news, bad news" technology. The information could be used to buttress your case in court, or it could be used against you. If you're in a collision while doing 74 mph in a 65 mph zone, will that count against you? Will your insurance company decline to renew your insurance? The black box would faithfully record your speed, but wouldn't note that most of the other traffic was going even faster.

As recorders become more sophisticated, and technology, particularly non-volatile memory, gets cheaper, black boxes could log not just a couple seconds of data but all data from the previous hour, day, or month, and they could upload the information to you for analysis. Again, this is great if you're monitoring teenage drivers, but not so great if the police are looking to write more speeding tickets and plugging in to your EDR. Your spouse can't testify against you in court, but your car can, if police get a warrant to seize and download the contents of the EDR. (Right now, it's not a simple process, and other technologies such as radar keep traffic ticket money flowing into municipal coffers.)

General Motors is one of the black-box pioneers and has equipped at least half its vehicles since the start of the decade. GM already posts its policies online. Essentially, the company won't use the data unless the cops ask for it, you sue GM ("the data is also used to defend our products in litigation"), or you sue someone else (or they sue you).

Are EDRs infallible? Some people involved in lawsuits says the sensors may get data wrong, such as vehicle speed, but the presumption of police and juries is that the technology just plain works.

Common on Commercial Vehicles

EDRs have made headway into the commercial vehicle market. They help ensure that fleet drivers comply with company, state, and federal regulations. Coupled with two-way radios, black boxes let fleets know where valuable cargo is at all times, or which courier truck to dispatch to make a pickup.

Black boxes are great for keeping other people honest. Police cars in Altamonte Springs, Florida, were suffering a rash of unreported damage. When the chief ordered that cars be equipped with a rudimentary black box system to track sudden deceleration (minor accidents) and date-stamp the results so they could be tracked back to the officers using the car, unreported damage dropped to nearly zero.

What the NHTSA Requires for 2011

The NHTSA doesn't require black boxes on cars, although odds are virtually all cars will have them by 2011. But for cars that have them, the NHTSA will require durability minimums, set a uniform minimum of information that must be captured, and require notification in the owner's manual. The NHTSA apparently did not issue rules requiring EDRs to remain active if they're installed, meaning a privacy-conscious owner should be able to disable or remove it.

Another government agency, the National Transportation Safety Board (which investigates plane crashes, too), urged that all cars should have them. The NHTSA hasn't ordered that, because of the cost.

Can Black Boxes Cut Insurance Costs?

In addition to making future cars safer, keeping police car fenders intact, and potentially chipping away at individual privacy, EDRs offer another plus for individual motorists. If you let your insurance company have access to the black box or install a second one, you could get lower rates by driving more when it's safer. That is, the same 20-mile trip on Sunday at 11 AM (when you're surrounded by churchgoers) would be less costly than making the same trip on a Friday at 11 PM, when taverns are in full swing. (You'd pay even less if you didn't make the trip at all.) Insurance would also be priced according to location: For instance, you'd pay more to drive in busy downtown Chicago than in placid, upscale Lake Forest.