The Problem: Alcohol consumption is a risk factor for many negative health outcomes. Alcohol consumption is a risk factor for cancer and other chronic conditions such as cirrhosis, and alcohol-impaired driving is one of the largest contributors to motor vehicle crashes CDC: Alcohol Use Factsheet. Each year in the United States, roughly 10,500 people die in motor vehicle crashes involving an alcohol-impaired driver. In 2016, more than one million people were arrested for driving under the influence of alcohol or narcotics. 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 Community Guide reviewers, there is strong evidence that laws adopting decreased BAC levels effectively reduce alcohol-related motor-vehicle deaths.
Additional Resources: The Community Guide