EFFECTIVENESS OF RAISING THE DRINKING AGE TO 21 IN ALL STATES IN THE U.S.

Transcription

1 EFFECTIVENESS OF RAISING THE DRINKING AGE TO 21 IN ALL STATES IN THE U.S. By James C. Fell National Center for Statistics & Analysis National Highway Traffic Safety Administration U.S. Department of Transportation Washington, DC USA Presented at: 11th International Conference on Alcohol, Drugs and Traffic Safety (T89) Chicago, IL October 26, 1989 SUMMARY: This paper discusses the history of minimum drinking age 21 (MDA 21) in the United States (U.S.), presents evidence as to why the drinking age was raised to 21, discounts myths perpetrated during resistance to MDA 21 laws, and summarizes the latest statistical studies of its effectiveness. Well controlled, scientific studies have shown average reductions on the order of 12-13% in fatal crash involvements of drivers of affected age groups in States that raised the drinking age. All 50 states in the U.S. now have MDA 21, and an estimated 5,656 lives have been saved since 1982 because of the law. HISTORY: Alcohol-related problems cost the U.S. society over $100 billion in health care, social services, property damage and lost work production (NTAAA, 1981). Recent efforts to prevent or control alcohol problems have concentrated on young people in order to reduce their effects and to curtail the development of problems later in life. Two general approaches have been taken in these efforts: educational and legal. Legal approaches have generally attempted to restrict the availability of alcohol to specific young age populations. Minimum drinking age laws were implemented in the U.S. after the repeal of the Prohibition in the 1930s. Most laws were set at age 21. There was very little activity between 1940 and Then, in 1970, the 26th Amendment to the U.S. Constitution extended voting rights to citizens between the ages of 18 and 21. This started a flurry of activity. Twenty nine states lowered their drinking age between 1970 and However, a number of studies concluded during that time period that reductions in the drinking age led to significant increases in alcohol-related crashes among young people (Douglass, et al., 1974). Between 1976 and 1983, sixteen states raised their minimum drinking age in response to this evidence. Citizen activist groups and other safety organizations in the early 1980s began advocating that all states should have MDA 21 to eliminate "blood borders" and send a consistent message to young people. The Presidential Commission on Drunk Driving recommended federal action to extend MDA 21 laws nationally. On July 17, 1984, Public Law was signed into law giving the states a substantial financial inducement to raise their drinking age to 21 (by withholding federal aid highway construction funds if they did not comply). Between 1984 and 1986, twenty eight states raised the drinking age to 21, and in 1987 and 1988 the remaining seven states passed MDA 21 laws (including the District of Columbia). 507

2 THE PROBLEM It has been known for some time that young drivers were overrepresented in alcohol-related crashes. In the early 1980s, teenaged drivers (15-19 years old) constituted only 7-10% of the licensed drivers but were involved in 18-20% of the alcohol-related fatal crashes (NHTSA, 1982, 1983). Traffic crashes continue to be the leading cause of death for teenagers -- over half of those are alcohol related. Each year between 3,000 to 4,000 teenagers die in alcohol-related crashes. A study of 1985 fatal crashes showed that teenaged drivers had the highest number of intoxicated drivers involved in fatal crashes per mile driven, compared to their older driver counterparts (Fell, 1987). The literature in general concludes that young drivers have these problems with alcohol for the following reasons (Wagenaar, 1983): * Inexperience with drinking combined with inexperience with driving increases the risk of a crash. * Alcohol exacerbates pre-existing impulsiveness and propensity toward risk taking, therefore increasing crash risk after drinking. * Young drivers have a high crash risk regardless of alcohol -- the probability of a crash is even higher after drinking. All of these hypotheses point toward drivers as an appropriate high risk target group. MPA 21 IMPACT OF HIGHWAY SAFETY Since 1984, there have been numerous studies of the effects of MDA 21 on crash reductions. In response to a request by the U.S. Congress, the General Accounting Office (GAO) reviewed existing evaluations of drinking age laws in 1987). Over 400 reports were reviewed; forty nine of them evaluated laws changing the drinking age. The GAO concluded that only 14 of those forty nine evaluation studies were of high quality and that their results were remarkedly consistent considering different evaluation approaches were used. GAOs major conclusion was: "Raising the drinking age has a direct effect on reducing alcoholrelated traffic accidents among youths affected by the laws, on average, across the states. The evidence also supports the finding that states can generally expect reductions in their traffic accidents, but the magnitude of the effects depends upon the outcome measured and the characteristics of the state." The report also stated that evidence exists that raising the drinking age also results in a decrease in alcohol consumption and in drinking and driving by those affected by the law. However, they also concluded that the evidence was insufficient at this time (1987) concerning the drinking age law effects on year olds, on border crossings, and other related matters. 508

3 MAJOR STUDIES OF EFFECTIVENESS In the GAO report, studies considered to be of "high quality" were well controlled scientific studies with most of the following characteristics: * They used time series analysis to take into account crash trends. * They used driver license data to control for changes in driver age populations. * They used "control states" that did not change their drinking age and/or "control age groups" not affected by drinking age laws. * They controlled for random fluctuations in the traffic crash picture by using appropriate statistical measures. * They did not use police reported alcohol involvement since it is generally underreported and widely variable from state to state and police jurisdiction to jurisdiction. In its place, these studies used either all fatal crashes or single vehicle nighttime fatal crashes or some other stable measure. MAJOR STUDIES OF EFFECTIVENESS In the GAO report, studies considered to be of "high quality" were well controlled scientific studies with most of the following characteristics: * They used time series ;analysis to take into account crash trends. * They used a driver license data to control for changes in driver age population. * They used "control states" that did not change their drinking age and/or "control age groups" not affected by drinking age laws. * They controlled for fandom fluctuations in the traffic crash picture by using appropriate statistical measures. * They did not use police reported alcohol involvement since it is generally underreported and widely variable from state to state and police jurisdiction to jurisdiction. It its place, these studies used either all fatal crashes or single vehicle nighttime fatal crashes or some other stable measure. Five recent studies used the above principles, and all found statistically significant reductions in fatal crash involvements of drivers affected by the drinking age change. The first two were conducted by the Insurance Institute for Highway Safety. The first (Williams, et al., 1983) found an average 28% reduction in nighttime fatal crashes of affected drivers in nine states that raised their drinking age. The second (DuMouchel, et al., 1985) studied twenty six states that raised their drinking age and found an average 13% reduction of nighttime fatal crashes for drivers affected by the age laws. Later in 1985, 509

4 NHTSA conducted two studies of effectiveness using quite different methodologies. Arnold (1985) found a 13% reduction in fatal crash involvements of the affected drivers pooled across 13 states (See Figure 1). Hoskin, et al. (1986) studied ten states and found a 5% average reduction in single vehicle nighttime fatal crashes of the affected driver age groups. Hoxie and Skinner (1987) found that a change in the NDA found 18 to 21 reduced fatalities involving the affected year-old drivers by approximately 11%. Recently, NHTSA conducted a follow-up study to the Arnold 13 state evaluation. In that study (Womble, 1989), (Womble) found that several years of additional data substantiated the Arnold conclusion that MDA laws are effective. Specifically, Womble found a 12% reduction in fatal crash involvements of drivers in the affected age groups (weighted average across all 13 states). Using the Arnold and Womble methodologies, NHTSA has estimated the lives saved byu minimum drinking age laws since 1982 (Figure 2). Overall, drinking age laws have saved approximately 9,000 lives and a total of 5,656 (lives) since 1982 when much of the activity began. OTHER EVIDENCE OF MDA 21 EFFECTIVENESS While the evaluation studies mentioned previously contain the most compelling evidence that MDA 21 has been effective, there is other data that also supports that conclusion. In 1985, the rate of intoxicated year-old drivers in fatal crashed (per capita) was 12% lower in states with MDA 21 compared to states without MDA 21 (net effect). This occurred despite a per capita alcohol consumption rate that was 11% higher in the MDA 21 states (Fell, 1987). A Department of Justice study reported that driving while intoxicated (DWI), arrest rates for year olds declined more than twice as much as those aged during (Greenfeld, 1988). The Fatal Accident Reporting System (FARS) in the U.S. indicated that 28% of the teenaged (15-19) drivers in fatal crashes were intoxicated in That proportion has dropped to 18% in 1988, a 36% reduction. That is the largest decrease in the proportion drunk for any driver age group (NHTSA, 1989). STUDIES INDICATING MDA 21 NOT EFFECTIVE A few studies have appeared in the literature and received much media coverage concluding that MDA 21 has not been effective (Holotin and Desario, 1985; Asch and Levy, 1986; Choukron, et al., 1986). A careful review of these studies by experts revealed numerous methodological problems and design flaws that were not consistent with the principles of well controlled scientific studies. These problems included the use of police reported alcohol involvement as a measure, desegregated data, no statistical methods employed, using only a single year's data, models that do not explain variation in the data, crude statistical treatments and awkward measurements of alcohol involvement. In short, the methodological problems with these studies were too numerous to be considered as valid evaluations. 510

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7 DISCOUNTING THE MYTHS OF 21 During the public debates, and especially after public law was signed in 1984, several concerns were raised about the possible consequences of MDA 21. Most of the concerns turned out to be myths. Here are some of the questions raised during these debates followed by the facts that discount them (Fell, 1986): o Won't the economic impact in a state be disastrous (bars and restaurants closing, large losses in the tax revenue, loss of jobs) if MDA 21 is adopted? In fact, in states that have adopted MDA 21, few (if any) bars or restaurants closed because of it and very little tax revenue has been lost. Alcohol consumption per capita was actually higher in MDA 21 states compared to non- (MDA)-21 states. States can and some do have legislation that permits 18 year olds to sell and serve alcohol, even though they can't legally purchase it. o Won't MDA 21 force young people to drink in uncontrolled environments (e.g., cars, parks, beaches)? On the contrary, lower drinking ages encourage that sort of behavior since teenagers can legally purchase alcohol in those non-21 states at much lower prices (than bars) at package and liquor stores and consume it in their cars or other uncontrolled places. Uncontrolled drinking is distinctly more prevalent in states with lower drinking ages according to several surveys. o At 18, a young adult is old enough to fight for their country, to vote, and to get married. Why not to drink alcohol? Evidence shows that year olds have the highest alcohol involvement rates in fatal crashes per mile driven. Society has a long tradition of rights and privileges at different ages in most U.S. states. For example: Drivers License Age 16 Voting Age 18 Serving in the U.S. House Age 25 of Representatives Serving in the U.S. Senate Age 30 Presidency of the U.S. Age 35 CONCLUSIONS Well controlled scientific studies consistently show MDA 21 to be effective in reducing fatal crash involvements of the affected driver age groups. States that have raised the drinking age to 21 have experienced (on the average) about a 12-21% decrease in affected driver involvements in fatal crashes. The proportion of teenage drivers in fatal crashes who were drunk has decreased 36% since 1982 (from 28% to 18%). The book by Wagenaar (1983) and the GAO report 1987) provide excellent reviews of the subject. An estimated 5,656 lives have been saved since 1982 due to MDA 513

8 21 laws. All fifty states and DC now have an MDA 21 law. Widely publicized studies concluding that MDA 21 have been ineffective were found to have numerous methodological problems after closer scrutiny. Many reasons for not raising the drinking age to 21 have turned out to be myths. In the future, stricter enforcement of MDA 21 laws must be demonstrated to the public if we can expect to continue to see these large reductions in fatal crash involvements of the affected age groups. REFERENCES Arnold, R. D. (1985). Effect of Raising the Legal Drinking Age on Driver Involvement in Fatal Crashes: The Experience of Thirteen States. National Highway Traffic Safety Administration, Washington, D.C., DOT HS Asch, P. and Levy, D. T. (1986). Does the Minimum Drinking Age Affect Traffic Fatalities? Rutgers University. Bolotin, F. N. and Desario, J. (1985). The Politics and Policy Implications of a National Minimum Drinking Age. Case Western Reserve University, Cleveland, OH. Choukroun, J. M., Ravn, I. and Wagner, C. (1986). Minimum Purchasing Age and Traffic Fatality: A Descriptive Analysis. The Wharton School, University of Pennsylvania, Philadelphia, PA. Cucchiaro, S., Ferreira, J., Jr., and Sicherman, A. (1974). The Effect of the 18 Year Old Drinking Age on Auto Accidents. Cambridge, MA: Massachusetts Institute of Technology, Operations Research Center. Douglass, R. L., Filkins, L. D. and Clark, F. A. (1974). The Effect of Lower Legal Drinking Ages on Youth Crash Involvement. Ann Arbor: The University of Michigan, Highway Safety Research Institute. DuMouchel, W., Williams, A. F., and Zador, P. (1985). Raising the Alcohol Purchase Age: Its Effects on Fatal Motor Vehicle Crashes in 26 States. Massachusetts Institute of Technology and Insurance Institute for Highway Safety, Washington, DC. Fell, J. C. (1986). Discounting the Myths of the 21 Drinking Age. Traffic Safety. National Safety Council, Chicago, IL, Volume 86, No. 2. Fell, J. C. (1987). Alcohol Involvement Rates in Fatal Crashes: A Focus on Young Drivers and Female Drivers. Proceedings of the 31st Annual Scientific Meeting of the American Association for Automotive Medicine. New Orleans, LA. GAO, General Account Office (1987). of Their Impact on Highway Safety. DC GAO/PEMD-87-lO. Drinking-Age Laws: An Evaluation Synthesis U.S. General Accounting Office, Washington 514

9 Greenfeld, L. A. (1988). Drunk Driving. Bureau of Justice Statistics Special Report, Washington, DC NCJ Hoskin, A. F. (1986). The Effect of Raising the Legal Minimum Drinking Age on Fatal Crashes in Ten States. National Safety Council, Chicago, IL. Hoxie, P. and Skinner D. (1987). A Statistical Analysis of the Effects of a Uniform Minimum Drinking Age. Transportation System Center, Cambridge, MA DOT HS NHTSA, National Highway Traffic Safety Administration (1982, 1983). Fatal Accident Reporting System Annual Report, Washington, DC, U.S. Government Printing Office. NHTSA, National Highway Traffic Safety Administration (1989). Fatal Accident Reporting System U.S. Department of Transportation, Washington, DC. NIAAA, National Institute on Alcohol Abuse and Alcoholism (1981). Alcohol and Health. Special Report to the Congress. NIAAA, Washington, DC, U.S. Government Printing Office. Wagenaar, A.C. (1983). Alcohol. Young Drivers and Traffic Accidents. Lexington Books, DC Heath and Co., Lexington, MA. Williams, A.F., Zador, P., Harris, S.S., and Karpf, R.S. (1983). The Effect of Raising the Legal Minimum Drinking Age on Involvement in Fatal Crashes. The Journal of Legal Studies. 12, Womble, K. (1989). The Impact of Minimum Drinking Age Laws on Fatal Crash Involvements: An Update of the NHTSA Analyses. National Highway Traffic Safety Administration, Washington, DC, DOT HS