The primary policy approach directed specifically at drinking and driving behaviors among adolescents and young adults has been a lowering of the legal blood alcohol concentration (BAC) limit for young drivers. Several non-randomized studies have ventured to assess the effects of these laws. Hingson, Heeren, and Winter (1994), for example, compared the fatal MVC experience of each of 12 states that lowered the legal BAC limit for young drivers before 1991 with the fatal MVC experience of a neighboring state that did not enact a similar policy change. The authors examined state-level data from FARS, described above, for all available years after the policy change and an equal number of years before the policy change in a given state. Fatal, single-vehicle crashes at night were used as a proxy for alcohol-related crashes, based on the argument that about half of fatal, single-vehicle, nighttime crashes among 15- to 20-year-olds involve alcohol use. In states that had lowered the legal BAC limit for young drivers, there was a drop in the percentage of adolescent fatal crashes that were single-vehicle crashes at night, relative to comparison states. There was no parallel decline among drivers 21 years and older, who were not targeted by the policy change. Moreover, the states that exhibited the largest law effects were those with the lowest BAC limits, of 0.0% or 0.02%. States with BAC limits of 0.04% to 0.06% showed little effect.

These findings suggest that lowering the legal BAC limit for young drivers may reduce alcohol-related MVC fatalities in this age group. Indeed, in a recent review of evaluations of such policy changes, Zwerling and Jones (1999) found that, although the available literature has important limitations, several non-randomized studies have suggested an effect of lower BAC limits on MVCs and/or associated injuries and fatalities. The authors indicate that these findings have been consistent across geographic areas, time, varying law specifications, and differing study designs. This replication bolsters the argument for the effectiveness of lower BAC limits.

Notably, a lower legal BAC limit for young and inexperienced drivers is among the approaches recommended by the Task Force on Community Preventive Services-an independent panel of experts, supported by the DHHS and CDC, that provides recommendations for community-level, public health interventions based on rigorous, systematic reviews of the research literature (Shults, et al., 2001; see also Task Force on Community Preventive Services, 2001). Furthermore, the Task Force strongly recommends both the enforcement of BAC limit laws via sobriety checkpoints and the preservation of a complementary policy that sets the minimum legal drinking age at 21 years.