The effects of minimum legal drinking age 21 laws on alcohol-related driving in the United States

McCartt, Anne T. / Hellinga, Laurie A. / Kirley, Bevan B.
Journal of Safety Research
April 2010

Objective: To examine trends in alcohol consumption and alcohol-related crashes among people younger than 21 in the United States and to review evidence on the effects of minimum legal drinking age (MLDA) laws.
Methods: Trends in alcohol-related crashes and alcohol consumption among young people were examined, and studies on the effects of lowering and raising the drinking age were reviewed.
Results: MLDA laws underwent many changes during the 20th century in the United States. Since July 1988, the MLDA has been 21 in all 50 states and the District of Columbia. Surveys tracking alcohol consumption among high school students and young adults found that drinking declined since the late 1970 s, and most of the decline occurred by the early 1990 s. These were the years when states were establishing, or reinstating, a MLDA-21. Among fatally injured drivers ages 16-20, the percentage with positive BACs declined from 61% in 1982 to 31% in 1995, a bigger decline than for older age groups; declines occurred among the ages directly affected by raising MLDAs (ages 18-20) and among young teenagers not directly affected (ages 16-17). Almost all studies designed specifically to gauge the effects of drinking age changes show MLDAs of 21 reduce drinking, problematic drinking, drinking and driving, and alcohol-related crashes among young people. Yet many underage people still drink, many drink and drive, and alcohol remains an important risk factor in serious crashes of young drivers, especially as they progress through the teenage years. Stepped-up enforcement of MLDA and drinking and driving laws can reduce underage drinking. Recent efforts to lower MLDAs to 18 and issue licenses to drink upon completion of alcohol education have gained local and national media attention. There is no evidence that alcohol education can even partially replace the effect of MLDA-21.
Conclusions: The cause and effect relationship between MLDAs of 21 and reductions in highway crashes is clear. Initiatives to lower the drinking age to 18 ignore the demonstrated public health benefits of MLDAs of 21.
Impact on industry: Lowering the drinking age to 18 will increase highway crash deaths among young people.