Is it .08 or more when I drive or .08 or more at the time I'm tested, or both, that will make me guilty of DWI?

Our law only provides that the crime of DWI occurs when a person drives, and at that time, has an alcohol concentration of .08 or more in his body. It is not a per se crime to have an alcohol concentration of .08 in the body either before or after one has driven. However, depending on the time the test is conducted, such an alcohol concentration may be relevant in determining if the person had a .08 or more alcohol concentration when the actual driving occurred.

The timing of the particular test in question presents a significant problem for both the prosecution and the defense. This dilemma arises because .08 alcohol concentration testing is hardly ever done at or immediately after driving. Rather, an alcohol concentration test is usually administered approximately 45 minutes to 1 hour and 15 minutes after driving. In such delayed testing, absent other information about the number of alcoholic drinks consumed, the type of drinks consumed, and knowledge of when the drinks were consumed, it is scientifically impossible to determine if the person was over, or more importantly for the innocent, under a .08 alcohol concentration at the time of driving.

For example, let's change our earlier scenario somewhat by having the person finish his fourth cocktail at 11:55 p.m. He leaves the smoke filled restaurant at 12:00 a.m. for a 5 minute drive home. However, this time instead of being stopped for speeding, he is stopped at 12:01 a.m. because the light over his license tag has burned out. The officer, having observed a fresh (strong) odor of an alcoholic beverage on the driver's breath and his smoke reddened eyes, arrests him for DWI. The officer then transports him to the station house for an alcohol concentration test. The test is given at 12:30 and its result is .08. Here, depending on the timing of the person's earlier consumption of alcoholic drinks, it is equally possible that earlier at 12:01 a.m., the person's alcohol concentration was .05, i.e., not guilty, or .15, i.e., guilty. In the final analysis on this point, it may not have been a smart thing for our person to have driven at all, but if he was the .05, he neither committed nor would have committed a DWI offense.