Blood Alcohol Content (BAC) Per Se Laws
Publication Date: 12/07/2009
The Problem:
The operation of motor vehicles while intoxicated is a major public health problem. Each year in the United States roughly 13,400 people die and an additional 255,500 are injured in motor vehicle crashes involving an alcohol-impaired driver. These crashes account for 32 percent of all U.S. traffic-related deaths and cost roughly $51 billion a year. CDC: Impaired Driving Factsheet.
The Law:
Blood alcohol per se laws set a blood alcohol limit at which an individual is considered legally impaired (i.e., impairment is “per se” because actual inability to function need not be established). Currently, all states set their BAC limit at 0.08 percent; some previously set the BAC levels at 0.10 percent. For examples of BAC per se laws, see Cal. Veh. Code §23152 (California), Fla. Stat. §316.193 (Florida), K.S.A. §8-1567 (Kansas), M.R.S. §2411 (Maine), N.M. Stat. Ann. §66-8-102 (New Hampshire), N.M. Stat. Ann. §66-8-102 (New Mexico), N.C. Gen. Stat. §20-138.1 (North Carolina), O.R.S. 813.010 (Oregon), Utah Code §41-6a-502 (Utah), 23 V.S.A. §1201 (Vermont), and Va. Code Ann. §18.2-266 (Virginia).
The Evidence:
In a Community Guide systematic review, Shults et al. reviewed eight studies that examined the impact of lowering the BAC limit to 0.08 percent on the rate of alcohol-related motor-vehicle deaths. Shults, et al. Reviews of Evidence Regarding Interventions to Reduce Alcohol-Impaired Driving. Am J Prev Med. 2001;21(4S):66-88.According to the reviewers, the underlying studies reveal a considerable association between the adoption of 0.08 percent BAC laws and a decline in alcohol-related motor-vehicle deaths; the median reduction in motor vehicle fatalities after the laws were adopted was 7 percent. Shults et al view these studies as strong evidence of the effectiveness of 0.08 BAC laws as a public health intervention. However, they caution that most of the BAC laws analyzed were enacted along with, or were supplemented by, other preventive drunk-driving laws, such as Administrative License Revocation (ALR) laws, making it difficult to isolate the exact magnitude of the impact of BAC laws.
The Bottom Line:
In the judgment of a Community Guide expert panel, there is strong evidence that laws adopting decreased BAC levels effectively reduce alcohol-related motor-vehicle deaths.
Additional Information:
The Community Guide provides online access to a table summarizing the results of each study it reviewed.
Additional Resources: The Community Guide
What are Evidence Briefs?
A Public Health Law Research Program “Evidence Brief” summarizes the research assessing the effect of a specific law or policy on public health.
Evidence Briefs are prepared by the staff of the National Program Office. Briefs are based on systematic literature reviews conducted by highly-regarded scholars and published by credible organizations or peer-reviewed journals. Evidence Briefs digest the best available evidence, but readers should bear in mind that even the best evidence may have limitations or deficiencies.
The evidence briefs are organized by topic and intervention. Each law or policy is classified as “effective,” “uncertain” or “harmful,” according to the conclusions of the expert reviewers. These are not independent conclusions of the NPO, nor do they reflect the views of the Robert Wood Johnson Foundation.
About the Links
Each Evidence Brief includes links to the study on which it is based. In many cases, the study is available in the public domain, but access to some may require a subscription.
