Original ArticlesEvaluation of the effectiveness of low blood alcohol concentration laws for younger drivers
Introduction
Compared to all age groups, young drivers have the highest risk of fatal crashes. Of the 56,793 American drivers involved in fatal crashes in 1996, 8,054 were 20 years of age or younger. These young drivers were involved in fatal crashes at a rate of about four times the rate for drivers 25 to 65 years old.1 Of these young drivers, 21% were killed in crashes in which the driver had a BAC of greater than 0.10%.
Over the years, we have had considerable success in lowering the percentage of teenagers killed in alcohol related crashes. In 1980, 53% of the teenage drivers killed in crashes had a blood alcohol concentration (BAC) of greater than 0.10%. By 1987, only 28% of the fatally injured teenage drives had BACs over 0.10.2 In 1996, only 21% had BACs over 0.10. In large part, this reduction in alcohol-related motor vehicle crashes among teenagers can be credited to the increase in the minimum drinking age to 21 years in all states.3
However, even with these laws, teenagers continue to drink and to die in motor vehicle crashes. To address this residual problem, 49 states have passed “zero tolerance” laws establishing lower legal blood alcohol limits for younger drivers than for adult drivers.
We conducted a systematic review to determine if “zero tolerance” laws have reduced the number of alcohol-related injuries and fatalities among young drivers.
Section snippets
Methods
Search strategy for identification of studies: Details of the search strategy are reported in the introductory article.4 The Cochrane collaboration methodology was used to search a variety of databases. Studies were not restricted to English and could come from both published and unpublished sources. We searched the following databases: MEDLINE 1966–1997, EMBASE 1974–1997, National Technical Information Service (NTIS), 1983–1997, Educational Research and Improvement Clearinghouse (ERIC),
Results
All six studies (see Table 1) showed a reduction in the outcome variable after the implementation of the law, although, for three of them, these reductions were not statistically significant. The methods for analyzing the data varied among the six studies. Thus, they can not be compared precisely. The study with the lowest reduction in the outcome variable10 was also the study with the least power. This study only had a power of 70% to detect a hypothetical 10% decline in serious casualty
Discussion
Since it is unlikely that these restricted blood alcohol concentration laws will ever be tested using a randomized controlled study, we must pay special attention to the methodologic weaknesses of ecologic studies. In pre- and post-studies and interrupted time series, the most troublesome threat to validity is historical bias.12 Historical bias refers to the possibility that something else may have occurred at the same time as the intervention and that this unknown factor, rather than the
Conclusions
The evidence appears sufficiently strong to justify the introduction of these restricted BAC laws in other jurisdictions. However, additional evaluations of these laws would seem prudent to address the possibility of historical bias. At least two such evaluations are currently underway: one in California and the other in Iowa. In 1997, the U.S. Congress voted to withhold a portion of Federal highway construction funds from states that did not adopt zero-tolerance laws. Consequently, by May
Acknowledgements
We would like to thank Kristi Ferguson, PhD, for reviewing this paper.
References (12)
- et al.
Systematic reviews of strategies to prevent motor vehicle injuries
Am J Prev Med
(1999) - et al.
Effect of the Victorian zero BAC legislation on serious casualty accidentsJuly 1984-December 1985
J Safety Res
(1989) - Department of Transportation (DOT), National Highway Traffic Safety Administration. Traffic Safety Facts, 1996....
- Sweedler BM, Quinlan KE. The National Transportation Safety Board’s proposals for reducing youth highway crashes: two...
- et al.
Effects of minimum drinking age laws on alcohol use, related behaviors and traffic crash involvement among American youth, 1976–1987
J Stud Alcohol
(1991) - Haque MO, Cameron M. Evaluation of the effect of the Victorian zero BAC legislation: July 1984-December 1985. 854...
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