Brief History of the MLDA
After Prohibition, nearly all states restricting youth access to alcohol designated 21 as the minimum legal drinking age (MLDA). Between 1970 and 1975, however, 29 states lowered the MLDA to 18, 19, or 20. These changes occurred when the minimum age for other activities, such as voting, also were being lowered (Wechsler & Sands, 1980). Scientists began studying the effects of the lowered MLDA, focusing particularly on the incidence of motor vehicle crashes, the leading cause of death among teenagers. Several studies in the 1970s found that motor vehicle crashes increased significantly among teens when the MLDA was lowered (Cucchiaro et al, 1974; Douglas et al, 1974; Wagenaar, 1983, 1993; Whitehead, 1977; Whitehead et al, 1975; Williams et al, 1974).
With evidence that a lower drinking age resulted in more traffic injuries and fatalities among youth, citizen advocacy groups pressured states to restore the MLDA to 21. Because of such advocacy campaigns, 16 states increased their MLDAs between September 1976 and January 1983. Resistance from other states, and concern that minors would travel across state lines to purchase and consume alcohol, prompted the federal government in 1984 to enact the Uniform Drinking Age Act, which mandated reduced federal transportation funds to those states that did not raise the MLDA to 21. Among alcohol control policies, the MLDA has been the most studied: since the 1970s, at least 70 studies have examined the effects of either increasing or decreasing the MLDA.