ORIGIN: Community Guide systematic review
Publication Date: 12/07/2009
Safety belts saved approximately 164,753 lives between 1975 and 2002 according to the National Highway Traffic Safety Administration (NHTSA). However, despite rising rates of safety belt use in the United States over the past 20 years, many American still do not consistently wear safety belts. David J. Houston and Lilliard E. Richardson, Jr., “Getting Americans to buckle up: The efficacy of state seat belt laws,” Accident Analysis and Prevention, 37 (2005) 1114–1120, at 1114
Primary enforcement seatbelt laws authorize police officers to stop drivers solely because individuals in a vehicle are not complying with safety belt laws. Secondary enforcement, in contrast, only authorizes enforcement of safety belt laws in conjunction with another offense (i.e., drivers cannot be stopped if the only offense is not wearing a belt). For example of primary enforcement safety belt laws, see GA Code Ann § 40-8-6 (Georgia) and Fla Stat § 316.614 (Florida).
In a systematic review, Dinh-Zarr et al. reviewed 13 studies that examined the effectiveness of primary enforcement safety belt laws as a means of reducing injuries related to motor vehicle crashes. Dinh-Zarr TB, et al. Reviews of evidence regarding interventions to increase the use of safety belts. Am J Prev Med. 2001;21(4S): 48-65. Nine of the reviewed studies compared the effectiveness of primary enforcement laws to that of secondary enforcement laws in the US; the other four measured the impact of changing from a secondary enforcement law to a primary enforcement law. Three studies focused their assessment on the impact of enacting primary enforcement legislation on specific populations (drunk drivers, African-American and Hispanics). The review found that primary enforcement laws are more effective in reducing fatal injuries and in increasing the frequency of safety belt use than secondary enforcement laws. Primary laws were found to reduce fatal injuries by a median 8 percent and to increase observed safety belt use a median 14 percent. Two studies found that primary enforcement laws increased safety-belt use by African-Americans and Hispanics compared to whites. There was no evidence in these studies that the difference was based on differential enforcement.
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.
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.