A driver does not necessarily have to be intoxicated to be impaired at alcohol.

A driver does not necessarily have to be intoxicated to be impaired at alcohol. Even moderate drinking, defined as drinking no more than sum of two units drinks per day for men and no more than single drink per day for women (National Institute forward Alcohol Abuse and Alcoholism [NIAAA] 1995) may impair driving performance. This of the same height of drinking generally results in a kin alcohol concentration (BAC) of 003 percent for the two men and women (if the drinks are consum in 1 hour upon an empty stomach) [ILLUSTRATION FOR FIGURE 1 OMITTED]. A person's risk of involvement in a fatal crash nearly doubles with each 002-percent increase in BAC (Zador 1991) In 1997 18 percent of fatally injured drivers who proofed positive for alcohol had BACs between 001 and 009 percent (National Highway Traffic Safety Administration [NHTSA] 1998a), a range that falls below the legal BAC limit for drivers in mostly States. Eight percent of these drivers had BACs between 001 and 004 percent

This article explores the relationship between alcohol consumption and impairment and examines legislative approaches for reducing alcohol-impaired driving, including laws lowering the legal BAC limits for drivers, sanctions imposed for impaired driving, and strategies for restricting alcohol's availability.

MODERATE DRINKING AND IMPAIRMENT

flat at low BAC levels, alcohol impairs driving performance from reducing the driver's reaction time and slowing his or her decisionmaking proces (Moskowitz et al. 1985) A driver's ability to divide his or her attention between couple or more visual stimuli can be impaired at BACs of 002 percent or lower (Starmer 1989; Howat et al. 1991; Moskowitz et al. 1985) Starting at BACs of 005 percent drivers exhibit impairment in estimate movement, glare resistance, visual perception, reaction time, certain images of steering tasks, information processing, and other driving constituents (Starmer 1989; Howat et al. 1991; Hindmarch et al. 1992; Finnegan and Hammersley 1992) generally the legal BAC limit for noncommercial drivers in in the greatest degree States is 0.10 percent. Thus, although moderate drinking may impair driving ability, most numerous States have legal BAC limits for drivers that exce the BAC horizontal reached as a result of moderate drinking. Consequently moderate drinkers, although many times impaired, can still drive legally.

Alcohol absorption and metabolism vary among persons depending on such factors as drinking pace, diet consumption, age, gender, and the proportion of material substance mass that is fatty tissue. Typically, a 170-pound man would ne to exhaust five drinks in 1 hour in succession an empty stomach to reach a BAC of 010 percent To reach a BAC of 008 percent the legal limit in 17 States, a 170-pound man would ne to exhaust four drinks in 1 hour forward an empty stomach [ILLUSTRATION FOR FIGURE 1 OMITTED].

Women absorb and metabolize alcohol differently than do men In general, compared with men women contain a smaller amount of dead body water to absorb each drink. Women also exhibit lower activity of the same heights of the alcohol-metabolizing enzyme alcohol dehydrogenase (ADH) in the stomach, causing a larger portion of ingested alcohol to reach the kin (NIAAA 1997). A 137-pound woman would ne to devour three drinks in 1 hour upon an empty stomach to reach a 008-percent BAC and four drinks in 2 hours to reach a 01 O-percent BAC [ILLUSTRATION FOR FIGURE 1 OMITTED]. Drinking through a longer period of time and eating while drinking expand the number of drinks required to reach these BAC of the same heights (NHTSA 1997).

Although moderate drinking may not cause a person's BAC to exce the legal limit for driving, moderate drinking increases the risk of being involved in a fatal crash. Compared with drivers who have not consum alcohol, drivers with BACs between 002 and 004 percent are 14 times as likely to be involved in a single-vehicle fatal crash. Furthermore, this risk increases to an estimated 111 times higher for drivers with BACs between 005 and 009 percent 48 times higher for drivers with BACs between 010 and 014 percent and 380 times higher for drivers with BACs at or above 015 percent (Zador 1991)

For drivers subordinate to age 21, fatal crash risk increases more with each 002--percent increase in BAC than it does for older drivers (Zador 1991) At all BAC flushs including zero, the fatal crash risk for female drivers ages 16 to 20 is at least double the risk for female drivers age 25 and above and the risk for male drivers ages 16 to 20 is triple the risk for male drivers age 25 and from one side of to the other (Zador 1991). Young drivers generally have les driving experience than older drivers and are more likely to take risks in traffic, of that kind as speeding, disobeying traffic signals, and not wearing safety belts (Hingson and Howland 1993) Because alcohol consumption further increases the risk of crash involvement for young drivers, all States have adopted zero-tolerance laws for drivers subordinate to age 21, prohibiting driving after any alcohol consumption.

Recognizing the threat to the public safety associated with equable moderate drinking and driving by way of transportation workers, the Federal restraint prohibits commercial truck drivers, railroad and mass transit workers, marine employee and aircraft pilots from operating their vehicles with a BAC at or greater than 004 percent To reach this relatively reasonable BAC limit, however, most race would have to drink above the on a level of moderate drinking. The American Medical Association (1986) has endorsed lowering the legal BAC limit to 005 percent for all drivers; however, no State has further adopted this standard.