Safety Belt Laws and Disparities in Safety Belt Use Among US High-School Drivers

摘要

Objectives. We compared reported safety belt use, for both drivers and passengers, among teenagers with learner’s permits, provisional licenses, and unrestricted licenses in states with primary or secondary enforcement of safety belt laws. Methods. Our data source was the 2006 National Young Driver Survey, which included a national representative sample of 3126 high-school drivers. We used multivariate, log-linear regression analyses to assess associations between safety belt laws and belt use. Results. Teenaged drivers were 12% less likely to wear a safety belt as drivers and 15% less likely to wear one as passengers in states with a secondary safety belt law than in states with a primary law. The apparent reduction in belt use among teenagers as they progressed from learner to unrestricted license holder occurred in only secondary enforcement states. Groups reporting particularly low use included African American drivers, rural residents, academically challenged students, and those driving pickup trucks. Conclusions. The results provided further evidence for enactment of primary enforcement provisions in safety belt laws because primary laws are associated with higher safety belt use rates and lower crash-related injuries and mortality. Motor vehicle crashes are the leading cause of death and acquired disability for teenagers in the United States, 1 and lack of safety belt use is a major contributing factor for injury. 2,3 Strong evidence indicates that safety belt laws are among the most important interventions in increasing safety belt use. 4 Safety belt laws have been enacted by states since 1984 and vary in the nature of their provisions. 5 In 2006, only 25 states and the District of Columbia had primary enforcement laws in effect: nonuse of a safety belt was considered a primary offense, and the law permitted police to stop motorists solely for not using a safety belt. The remaining 24 states with safety belt laws considered nonuse of a safety belt a secondary offense and permitted police to issue a ticket for belt nonuse only if the vehicle was stopped for another offense, such as speeding. New Hampshire was the only state with no safety belt law. As of March 2012, 17 US states still have secondary safety belt laws in effect, and New Hampshire still has no safety belt law at all. 6 Previous research has shown that primary safety belt laws are associated with higher safety belt use and lower crash-related injuries and mortality in the general population as compared with secondary laws. 7–17 Few studies have examined the effect of primary versus secondary enforcement safety belt laws on belt use behavior and injury outcomes in teenagers. Such a specific study is warranted because of the lack of studies on the association between graduated driver licensing stages and safety belt use in the United States, and effective policies might be needed to increase use. Previous studies have reported higher belt use by teenaged passengers in primary than in secondary enforcement states, 18–20 but no studies have examined the association in novice teenaged drivers. Self-reported safety belt use increased between 1986 and 2000 among high-school 12th grade students in states with secondarily enforced safety belt laws. 21 In addition, mandatory safety belt laws adopted by US states between 1991 and 2005 have been associated with lower deaths and serious injuries and higher safety belt use among high-school students when riding as passengers. 19 The current study extended this line of research by establishing the association between safety belt law provisions and both teenaged passengers and teenaged drivers. It is particularly important to know how the prevalence of safety belt use among teenagers varies as they progress through the licensing process, from learners—who are supervised at all times by adults in the vehicles—to unrestricted, fully licensed drivers, and how this is associated with the enforcement status of state safety belt laws. Because teenaged drivers are most likely to crash in the first months after licensure, 22,23 wearing safety belts at the time of the crash is of great importance to reduce the severity or incidence of injury. Because reported safety belt use is higher among drivers than among passengers, 24–28 the aim of this study was to compare reported safety belt use, both as drivers and as passengers, among novice teenaged learners and among provisional and unrestricted teenaged drivers in primary versus secondary enforcement states.