The Effectiveness of a 0.05 Blood Alcohol Concentration (BAC) Limit for Driving in the United States

This article reports on a comprehensive review of state laws and research on blood alcohol concentration (BAC) limits for drivers. The study was undertaken in response to recent recommendations from the National Transportation Safety Board (NTSB) that states should establish a per se BAC limit of 0.05 or lower for all drivers who are not already required to adhere to lower BAC limits. The authors found that virtually all drivers are impaired regarding in some driving-related performance measures at a 0.05 BAC. The article is set up as a series of “issues” or myths about blood alcohol levels, law enforcement, and societal norms; each of these issues is addressed in turn. The risk of being involved in a crash increases significantly at 0.05 BAC and above. The authors estimated that the relative risk of being killed in a single-vehicle crash with BACs between 0.05–0.079 is 7–21 times higher than for drivers with zero alcohol blood levels. The research also supported strategies that lowered the BAC limit from 0.08 to 0.05, shown to be an effective countermeasure in numerous countries around the world. Other issues that the authors discuss include the BACs in heavy drinkers, concerns that the US public will not support a 0.05 limit, police enforcement of an 0.05 BAC limit, the impact of reducing the BAC limit for adults on reducing fatal crashes in underage drinking drivers (who often already have an 0.02 zero tolerance law they must abide by), and the support of worldwide scientific and safety organizations in establishing an 0.05 BAC limit. The authors conclude that lowering the BAC limit for driving from the current 0.08 to 0.05 would have substantial positive impact on reducing the number of people who drink and drive in the United States. However, in the past 15 years, progress in reducing the proportion of drivers with illegal BACs in fatal crashes has lost momentum.


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  • Accession Number: 01539672
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Sep 4 2014 4:38PM