In all 50 states, the legal limit for drunk driving is a blood alcohol concentration (BAC) level of .08. A 120-pound woman can reach a .08 BAC level after only two drinks and a 180-pound man can be at .08 after only four drinks.
A "drink" is either one shot of liquor, a five-ounce glass of wine or one beer, all of which contain the same amount of alcohol.
At a .08 BAC level, drivers are so impaired that they are 11 times more likely to have a single-vehicle crash than drivers with no alcohol in their system. But 25 years of research has shown that some impairment begins for both males and females even after one drink.