Politicians get away with stuff we'd love to do—such as drive 85 miles per hour on the highway. New Jersey governor Jon Corzine's SUV was doing 91 mph moments before the accident that nearly killed him. We know, because a black box told us so. If you're worried about an encroaching brave new world in which our every action in a car is monitored by technology, you're too late: The black box is here, and it's probably in your car, too.

Most cars have event data recorders (EDRs), or black boxes, just as airplanes do. They've been in some cars since 1995, as I've noted before, and they'll be mandatory in all cars as of 2011. Even now, you probably have at least a rudimentary event data recorder. The one in Corzine's Chevrolet Suburban captures the most recent 5 seconds of speed and other data and locks it in if there's a crash.

An EDR can capture enough information to suggest how much the car contributed to the accident versus the driver's responsibility, and also compare the culpability of other cars involved. EDRs have the ability to capture speed, whether the brakes are on, the throttle position, whether ABS (anti-lock braking) is on, whether stability control is in use, the yaw rate (spinning), whether seat belts are worn, the sequence of airbags deployed, the turn-signal status, the steering wheel angle, whether headlights are on, and whether wipers are on (indicating a wet road surface). Not all data is currently captured. Aggregate this information from thousands of crashes, and researchers can learn more about making cars safer.

But pull one black box out of one wrecked car—yours—and you may have a tougher time convincing the insurance company that you were driving 65, minding your own business, when the car suddenly headed for the ditch even though you had the brakes on. Pull the black box out of both cars in a two-car accident, and maybe you've got a chance to prove your point: You were doing 69 mph in a 65 zone, while the other guy was doing 78 with no blinker on, when he changed lanes and tagged your front fender, just as you said.

In the case of Corzine, state police said that of course the NJ governor's trooper-driver-bodyguard wasn't speeding, until the black box said he was. Then they said it's essential to speed to avoid being boxed in by other cars that could contain would-be threats. (At 91 mph, it's unlikely you'll be boxed in from behind.) It appears likely Corzine's driver caused the accident, because he came up so quickly on other traffic. Among traffic researchers, it's an axiom that speed doesn't cause accidents as much as speed differential. If the governor's transporter is doing 90 while everyone is doing 80, no big deal. But 90 versus 65? That's a big deal.

Also, when police use video technology and wireless mikes to record traffic stops, it essentially ends police-profiling stops of blacks and Hispanics, which was a huge problem in New Jersey a decade ago. It also has ended false counter-charges of harassment, since good behavior by troopers is on the record, too.

Had the Audi 5000 had an event data recorder in the 1980s, the flap over unintended acceleration would almost certainly have been resolved this way: driver error, end of story. Even people with enough money to buy big Audis can absent-mindedly step on the gas and believe it's the brakes, especially when Audi brake and gas pedals are fractionally closer for better heel-and-toe braking. Sometimes you run into the garage wall, and occasionally your child; then it's a tragedy.

Corzine has been one of America's most intriguing and possibly able politicians—imagine, a Democrat from the highest levels of Wall Street; social conscience plus fiscal conservatism—but then he's got problems with lady friends who're tangled in New Jersey politics; gaps in his knowledge base, even if his heart's in the right place (informed that the drinking age was 21, not 18, Corzine said what a lot of us think: If you're old enough to get shot at in Iraq, you're old enough to have a beer); and a trace of arrogance over laws he doesn't like (such as mandatory seat belts).

There's editorial hand-wringing about Corzine's speed and how politicians need to stick to the speed limit when on official business. Like that's going to happen. Instead, how about letting us drive at the speed politicians feel is reasonable and prudent? What's sauce for the goose…