Dear Cecil: In The Bad Girl's Guide to the Open Road, Cameron Tuttle suggests the following technique for getting out of a DUI: If you get pulled over, immediately step out of the car with a bottle of your favorite liquor and chug a couple shots' worth. The officer now has no way of proving you were drinking before you got out of the car. Interesting thought, but is this actually true? Perhaps the most the officer could do would be to cite you for public intoxication/open container in public? Hazle Weatherfield, via the Straight Dope Message Board

Cecil replies:

Yes, Hazle, that’s an interesting thought. But can you imagine this ridiculous gambit actually working here in reality land? I didn’t think so. Tuttle concedes as much, prefacing her advice with the comment that “if you’ve been drinking and have an open bottle of hard liquor in your car, you’re already in deep shit. So what do you really have to lose?”

Let’s back up a bit. Prior to Breathalyzer-type technology, which measures blood alcohol concentration (BAC), drunk driving was a tough charge to make stick — prosecutors needed witnesses to testify about the defendant’s slurred speech, unstable gait, and so on. Things got only slightly easier after BAC testing devices became available in the 1930s. Although a high BAC was telling evidence, you still needed corroborating testimony about drunken behavior, plus you had to have an expert witness explain what BAC meant. Eventually states wised up and passed “per se” laws, which defined drunk driving quite simply: operating a vehicle with a certain minimum BAC. Today it’s .08 percent.

Depending on how the law is written, this approach can still present problems for prosecutors. BAC, of course, is measured only after the driver’s been pulled over, enabling some to claim their BAC increased after they stopped driving. There’s something to that argument, as BAC typically peaks 30 to 60 minutes after your last drink.

Some states get around this by defining drunk driving as (a) operating a vehicle and (b) having a BAC over the limit within a given time afterward. In these jurisdictions it’s legally irrelevant whether the offending BAC was achieved after you stopped driving. Certain states, however, do permit the defendant to prove postoperation consumption was responsible for the offending BAC.

So maybe you could weasel your way out of an incriminating Breathalyzer test. That doesn’t mean Tuttle’s stratagem will work. Courts in New Jersey, evidently a hotbed for this sort of thing, have dubbed her approach the “glove box defense,” after the presumed location of the driver’s emergency liquor stash. In one classic early case, State v. Lizotte (1993), police pulled the defendant over for speeding. He seemed drunk when questioned, had an open beer can on his dashboard, and blew BACs of .13 and .14. He was convicted of drunk driving but appealed the verdict, claiming he’d quickly downed the beer after being pulled over to avoid being charged with an open-container violation. Because he’d consumed alcohol after he’d stopped driving, he argued, the Breathalyzer test was invalid.

Nuh-uh, said the appeals court. Its implicit rationale: You’re operating a motor vehicle whenever you’re in control of it, not just when you’ve got it in motion. (In fact, people have been convicted of drunk driving for sleeping it off in a parked car.) That you claimed to have been stopped when you drank the beer makes no difference; you were still operating the vehicle.

You see what this means. If you’re in a jurisdiction that accepts a broad definition of operating a vehicle, chugging a bottle in front of a cop won’t help you, even if you’re physically outside the car. A court could easily conclude that technically you were still in control.

Despite its futility, the glove box defense apparently remains popular among New Jersey drunk drivers and their lawyers. In one 1999 incident, a guy had three beers at a tavern, then hit a car in the parking lot; he was subsequently convicted of DUI despite claiming that his BAC results were misleadingly high because following the collision he “drank whiskey from a VO bottle that he kept in his car.” More recently, the judge in a similar case noted, “To dismiss defendant’s charges based upon this finding would lead to the absurd result that anyone wishing to avoid a DWI conviction would merely have to drink alcohol after operation.” The glove box defense has been written up in practice guides for New Jersey lawyers as an example of a stunt not to try.

OK, you say, I won’t try it in Jersey. That still leaves 49 other states, the District of Columbia, and numerous territories and minor outlying islands. True, but bear in mind that state courts freely borrow legal precedents from one another. (Minnesota and Indiana, the other two main sources of case law on this point, are largely in line with New Jersey.) But who knows? Maybe they do things differently in Guam. Give it a whirl and let us know.

Cecil Adams

Send questions to Cecil via cecil@straightdope.com.