ave. = 1 drink/hour
depends on weight and metabolism. 1 drink refers to a beer, a glass of wine, or a single shot.

safe answer is an hour.

I Agee with VoodLogic . I also heard that a womans BAL ( blood alcohol level ) would be higher. That is just something I remember hearing .Would be something to add anouther varitable and could change the answer .

After alcohol is absorbed into the bloodstream it leaves the body in two ways. A total of about ten percent leaves through the breath, perspiration, and urine. The remainder is broken down through the process known as metabolism.

The rate at which alcohol is metabolized is the same for virtually everyone regardless of their height, weight, sex, race or other such characteristics.

Alcohol is metabolized at the rate of .015 of blood alcohol concentration (BAC) every hour. Thus, for example, a person with a very high BAC of .15 will have no measurable alcohol in the bloodstream after ten hours (.15 divided by .015 = 10).

It’s important to remember that BAC can continue to rise for a period of time after the last drink is consumed.

http://www2.potsdam.edu/hansondj/DrivingIssues/1127227453.html