TRENDS IN DRINKING AND DRIVING
This section examines trends in drinking and driving over approximately the past 20 years. Trends are reported based both on surveys of drivers stopped at random while driving and on records of alcohol–related fatal crashes.
National Roadside Surveys
National roadside surveys were conducted in 1973, 1986, and 1996. Drivers were stopped between 10:00 p.m. and 3:00 a.m. on Friday and Saturday nights, when most drinking occurs (Voas et al. 1997). Similar sites and sampling procedures were used in each survey.
Overall, the proportion of drivers with positive BACs decreased from 36 percent in 1973 to 17 percent in 1996. The decline was greatest for drivers with lower BACs (0.005 to 0.049 percent).
The percentage of drivers under age 21 who had BACs of 0.10 or higher fell from 4.1 to 0.3 percent, representing the greatest proportional decline for any age group. Among 21– to 25–year–olds, the proportion of drivers with BACs of 0.10 percent or higher decreased from 5.7 to 3.8 percent.
The percentage of drivers with BACs of 0.10 percent or higher declined from 3.0 to 1.5 percent among females and from 5.5 percent to 3.5 percent among males. BAC levels also varied by race/ethnicity. Among White drivers, the proportion with positive BACs declined from 5.1 to 2.3 percent. Among African American drivers, the proportion with positive BACs declined from 6.0 to 3.6 percent. By contrast, the proportion of Hispanic drivers with positive BACs increased from 3.3 to 7.5 percent. The number of Hispanic drivers surveyed increased sevenfold during that time period (Voas et al. 1997).
Traffic Fatality Trends
Consistent with the roadside survey results, traffic deaths involving alcohol declined markedly from the early 1980s to 1996, but during the last 6 years the downward progress has abated and alcohol–related traffic deaths have actually increased somewhat (NHTSA 2003a).
As shown in figure 1, in 1982 when NHTSA first made nationwide estimates, there were 26,172 alcohol–related traffic deaths. Alcohol–related traffic deaths were 33 percent lower in 2002, at 17,419. During the same timeframe, traffic deaths that did not involve alcohol increased 43 percent, from 17,773 to 25,396. For every 100 million vehicle miles traveled, the rate of both non–alcohol–related and alcohol–related traffic deaths declined (19 percent and 62 percent, respectively). This is attributable to a 77–percent increase in the number of miles driven in the United States, from 1,595 billion in 1982 to 2,830 billion in 2002.
Figure 1 Trends in alcohol–related and non–alcohol–related traffic fatalities, 1982 through 2002. Alcohol–related traffic deaths were 33 percent lower in 2002 than in 1982. During the same time, traffic deaths that did not involve alcohol increased 43 percent.
SOURCE: NHTSA 2003a.
Although total alcohol–related traffic fatalities have decreased, the degree of decline varies when BAC is considered. The numbers of traffic deaths involving people with BACs up to 0.08 percent had the smallest proportional decline (19 percent) from 1982 to 2002 (see figure 2). Traffic deaths among people with BACs of 0.08 percent and higher declined 35 percent, and those involving people with BACs of 0.15 percent and higher declined 37 percent.
Figure 2 Trends in number of alcohol–related traffic fatalities for different BACs, 1982 through 2002. Traffic deaths involving people with BACs up to 0.08 percent had the smallest proportional decline (19 percent) from 1982 through 2002. Traffic deaths among people with BACs of 0.08 percent and higher declined 35 percent, and those involving people with BACs of 0.15 percent and higher declined 37 percent.
SOURCE: NHTSA 2003a.
Declines in traffic deaths since 1982 have not varied much by gender. In 1982, 20,365 men and 5,805 women died in alcohol–related crashes. In 2002, the number of male alcohol–related traffic deaths was 13,500, a 34–percent decline. Among women, 3,910 deaths were recorded in 2002, a 33–percent reduction. However, there have been greater proportional declines in the numbers of male drivers in alcohol–related fatal crashes. Since 1982 the number of male drivers in alcohol–related fatal crashes declined 37 percent, from 19,478 to 12,270, whereas the number of female drivers only declined 22 percent, from 2,854 to 2,216.
Young adults have experienced a greater proportional reduction in alcohol–related traffic deaths than older adults in the last 20 years. Sixteen– to 20–year–olds have had the greatest decline in alcohol–related traffic deaths since 1982, down 56 percent, from 5,244 to 2,329 (see figure 3). There was a 62–percent decline in traffic deaths among young people in which the person with the highest BAC in the crash had a BAC above 0.15 percent, and a 59–percent decline in deaths where BACs exceeded 0.08 percent. Alcohol–related traffic deaths declined 47 percent among 21– to–29–year–olds (from 8,707 to 4,595) and 7 percent among 30– to 45–year–olds (from 6,141 to 5,682). The smallest proportional decline was observed among 46– to 64–year–olds, where only a 1–percent reduction occurred, from 3,215 to 3,192 (NHTSA 2003a).
Figure 3 Trends in number of alcohol–related traffic fatalities for different age groups, 1982 through 2002. Sixteen– to 20–year–olds have had the greatest decline in alcohol–related traffic deaths since 1982, down 56 percent. Alcohol–related traffic deaths declined 47 percent among 21– to 29–year–olds and 37 percent among 30– to 45–year–olds. The smallest proportional decline was observed among 46– to 64–year–olds, where only a 1–percent reduction occurred.
SOURCE: NHTSA 2003a.
Over the past two decades, fatal crashes not involving alcohol increased in each age group, indicating that the overall decline in alcohol–related deaths during this period was independent of changes in the age composition of the U.S. population.
The greater decline in alcohol–related traffic deaths among 16– to 20–year–olds is in part attributable to the adoption of age 21 as the legal drinking age, which occurred in all States by 1988. A review of more than 49 studies of changes in the legal drinking age revealed that in the 1980s and 1990s when many States lowered the legal drinking age, alcohol–related traffic crashes involving drivers under 21 increased 10 percent. In contrast, when States increased the legal drinking age to 21, alcohol–related crashes among people under 21 decreased an average of 16 percent (Shults et al. 2001).
Zero tolerance laws have also contributed to these declines. These laws, which have been enacted in every State, make it illegal for drivers under 21 to drive after any drinking. A comparison of the first eight States to adopt zero tolerance laws with nearby States without these laws revealed a 21–percent decline in the proportion of fatal crashes among drivers under 21 that were of the type most likely to involve alcohol (i.e., single–vehicle fatal crashes at night) (Hingson et al. 1994). This type of crash among adults (i.e., those age 21 and older) declined 3 to 4 percent both in zero tolerance States and comparison States. Wagenaar and colleagues (2000) found that in the first 30 States to adopt zero tolerance laws, relative to the rest of the nation, there was a 19–percent decline in the proportion of people under 21 who drove after any drinking, and a 23– percent decline in the proportion of those driving after five or more drinks (based on survey results).
Despite marked reductions in the proportions of motorists who drive after drinking and in alcohol–related traffic fatalities, alcohol–impaired driving remains a serious threat to the nation’s health. In 2002, 41 percent of traffic deaths and 9 percent of traffic injuries were alcohol related. As many as 44 percent of people killed in crashes involving drinking drivers are people other than the drinking driver.
Fatal crash risk was at least 11 times higher for drivers with BACs of 0.08 percent, the legal limit for intoxication in most States, than for drivers with zero BACs. Fatal crash risk was 52 times higher for male drivers ages 16 to 20 with BACs of 0.08 percent, compared with zero–BAC drivers of the same age. Fatal crash risk nearly doubled with each 0.02–percent increase in BAC.
Traffic deaths are most likely to be alcohol related among males, Native Americans and Mexican Americans, people ages 21 to 45, those who die in motor vehicle crashes on weekend nights, and people with symptoms of alcohol dependence.
National surveys also reveal that males and people ages 21 to 45 are the most likely to drive after drinking. Although drivers ages 16 to 20 accounted for only 12 million of 957 million drinking–driving trips in 1999, the average BAC among young drinking drivers was 0.10 percent, more than three times the average BAC level for all drinking drivers. Drivers under 21 in all States tend to drive with more passengers in their vehicles. Despite laws making it illegal to sell alcohol to people under 21 and for drivers that age to drive after any drinking, most people in this age group who drive after drinking are unaware that it is illegal to do so.
Recent evidence indicates that the younger people are when they begin drinking, the greater their likelihood of becoming alcohol dependent, which may increase their risk of alcohol–related crash involvement not only during adolescence but during adulthood as well (see the sidebar below).
Age of Drinking Onset and Alcohol–Related Crash Involvement
Evidence about the relationship between age of drinking onset and alcohol–related crash involvement is available from the National Longitudinal Alcohol Epidemiologic Survey (NLAES). This 1992 national survey of adults age 18 and older used the Alcohol Use Disorders and Associated Disabilities Interview Schedule (AUDADIS) (Grant and Hasin 1992) to determine whether respondents could be diagnosed with alcohol dependence or alcohol abuse, based on criteria from the Diagnostic and Statistical Manual, Fourth Edition (DSM–IV) (APA 1994).
NLAES data showed that the younger respondents were when they first began to drink alcohol, the more likely they were to develop alcohol dependence (Grant 1998). Among both males and females and people with and without a family history of alcoholism, those who began drinking regularly before age 14 were at least three times more likely to develop alcohol dependence during their lives than those who waited until age 21 or older to drink (Grant 1998).
Further analyses of that survey revealed that even after controlling for history of alcohol dependence, those who started drinking at younger ages were more likely to drink heavily (five or more drinks per occasion) with greater frequency (Hingson et al. 2000). Moreover, the younger people were when they began drinking, the greater their likelihood of driving after drinking too much and of being in motor vehicle crashes because of drinking (based on self–report). Compared with respondents who waited until age 21 or older to start drinking, those who began drinking before age 14 were three times more likely to report ever driving after drinking too much (58 percent vs. 18 percent) and four times more likely to report doing so in the year prior to the survey (13 percent vs. 3 percent). Those who started drinking before age 14 were seven times more likely to have been in a drinking–related motor vehicle crash at any time in their lives (14 percent vs. 2 percent) and in the past year (0.7 percent vs. 0.1 percent) (Hingson et al. 2002). Because the average age of respondents in the survey was 44, these findings indicate that those who start drinking at an early age are more likely to be in alcohol–related motor vehicle crashes during both adolescence and adulthood.
It is noteworthy that this pattern of relationships was found even after controlling for history of alcohol dependence, frequency of heavy drinking, years of drinking, age, gender, race/ethnicity, education, marital status, smoking, and illicit drug use, all of which were related to the age at which respondents began to drink.
Research has long indicated that raising the minimum legal drinking age (MLDA) to 21 has reduced alcohol–related crashes among drivers under 21 (Shults et al. 2001). This study raises the possibility that delaying underage drinking may reduce alcohol–related crash involvement among adults as well (Hingson et al. 2002). In an analysis of the effects of increasing the MLDA to 21, O’Malley and Wagenaar (1991) found that people who grew up in States with the legal drinking age of 21 not only drank less when they were younger than 21, they also drank less from ages 21 to 25.
— Ralph Hingson and Michael Winter
American Psychiatric Association (APA). Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. Washington, DC: APA, 1994.
GRANT, B. The impact of family history of alcoholism on the relationship between age of onset of alcohol use and DSM–III alcohol dependence. Alcohol Health & Research World 22(2):144–147, 1998.
GRANT, B.F., and HASIN, P.S. The Alcohol Use Disorders and Associated Disabilities Interview Schedule. Rockville, MD: National Institute on Alcohol Abuse and Alcoholism, 1992.
HINGSON, R.; HEEREN, T.; JAMANKA, A.; and HOWLAND, J. Age of drinking onset and unintentional injury involvement. JAMA: Journal of the American Medical Association 284(12):1527–1533, 2000.
HINGSON, R.; HEEREN, T.; LEVENSON, S.; et al. Age of drinking onset, driving after drinking and involvement in alcohol–related motor vehicle crashes.Accident Analysis and Prevention 34:85–92, 2002.
O’Malley, P.M., and WAGENAAR, A.C. Effects of minimum drinking age laws on alcohol use, related behavior, and traffic crash involvement among American youth: 1976–1987. Journal of Studies on Alcohol 52(5):478–491, 1991.
SHULTS, R.; ELDER, R.; SLEET, D.; et al. Reviews of evidence regarding interventions to reduce alcohol–impaired driving. American Journal of Preventive Medicine 21(Suppl. 4):66–88, 2001.
END OF SIDEBAR
Drinking drivers are less likely to wear safety belts, and the higher the BAC of a fatally injured driver, the less likely he or she was to have been wearing a safety belt. Failure to wear safety belts increases the risk of injury or death in fatal crashes.
Despite overall marked reductions in alcohol–related traffic deaths since the early 1980s, there has been little reduction since the mid–1990s, and alcohol–related traffic deaths have increased slightly in the past 3 years. Proportional reductions in alcohol–related traffic deaths were smaller among people with prior drinking and driving offenses than among those without previously recorded offenses.
Nationally, the number of arrests for drinking and driving increased sharply from the late 1970s to the early 1980s, but were substantially lower in the 1990s.
A national survey conducted in 1999 revealed that only 30 percent of adults age 16 and older believed it at least somewhat likely that if they drove after drinking too much they would be stopped by the police, arrested, and convicted. Only 2 percent believed it almost certain that all those things would happen. In 1999, according to that survey, 82 million (or 10 percent) of drinking and driving trips involved a driver with a BAC of 0.08 percent or higher. However, only 1.5 million drivers were arrested for driving under the influence of alcohol or drugs that year.