Diving Laws

A .10 BAC (Blood Alcohol Concentration) means that alcohol constitutes one-tenth of one percent of all blood in the driver's system. While this amount may not seem large, a 10 BAC has an adverse effect on reaction time, vision, judgment, and the ability to brake and control speed; as a depressant, even small quantities of alcohol, in any form, reduces sensorimotor coordination. Moreover, drivers with a .10 BAC are seven times more likely to be involved in an accident than are sober drivers; the risk of an accident is twenty-five times greater at .15 BAL (about eight drinks in an hour) and increases 100-fold at .20 BAC. Not only does the likelihood of a crash occurring increase as the BAL increases, but the higher the BAC the more serious the crash. Commonly observed BAC levels of arrested drunk drivers are in fact much higher than the .10 minimum. The average BAC of 7,000 first-offender drunk drivers in Albuquerque was .168. And in New York, which requires that all persons with a prior drunk driving conviction be screened for alcohol problems, the average BAL of 300 multiple-offenders interviewed in 1985 was .20.

The BAC level is a result, primarily, of three factors: the amount of food in the stomach (more food slows the rate at which alcohol is absorbed into the bloodstream), the rate at which liquor is consumed over a given time period, and body weight. On an empty stomach, it would take about five (80-proof one-ounce) drinks consumed in an hour for a 150-pound person to be legally intoxicated, that is, to reach a .10 BAC . A 120-pound person could reach .10 by downing four drinks in an hour, while it would take six drinks for a 180-pound person to do so. The same individuals would have to consume considerably more liquor to reach .10 if they had recently eaten, were eating and drinking at the same time, or if the drinking interim were extended. Half of the drunk drivers involved in fatal crashes have a BAC of .20-twice the legal limit for intoxication. To have a .20 BAL, a 160-pound person would have to consume eleven drinks of 80-proof liquor in one hour on an empty stomach.

As part of the anti-drunk driving movement , reformers have urged states to reduce the threshold of driver intoxication from .10 to .08, a more stringent standard commonly used in many European countries, but such efforts have been stifled by the alcohol industry and business community, who claim that doing so would needlessly penalize the social drinker. As of 1989, only Maine, Oregon, and Utah had adopted a .08 BAC, and six other states (including California) were considering doing so. No state has yet implemented the American Medical Association position favoring a .05 standard of intoxication, even though recent studies show that most people become noticeably driving-impaired at this BAL and that the risk of a .05 driver having an accident is five times that of a nondrinking driver.