There is a general agreement that donning a seatbelt reduces the risk of fatal and nonfatal injuries in the event of an MVC. The National Highway Traffic Safety Administration [NHTSA] has issued a report that combines information across various data sources to estimate the protective value of seatbelts (1984). According to these estimates, based on data regarding passengers in the front seat of a passenger vehicle, the use of a manual lap/shoulder belt approximately cuts in half the risk of fatality and of moderate to serious injury in the event of an MVC. Wearing a manual lap belt decreases the risk of fatality by about 35% and of moderate to serious injury by about 30%. However, a sizable fraction of adolescents are not benefiting from the protection of seatbelts. According to the 1999 YRBS, about one of every six high school students reports rarely or never wearing seatbelts when riding as a passenger in a car or truck (Kann, et al., 2000). High school boys are more likely than are high school girls to report rarely or never using seatbelts (20.8% vs. 11.9%).

In a school-based seatbelt promotion effort, Martinez, Levine, Martin, and Altman (1996) evaluated the effects of a one-week educational program that was integrated into a high school physics class. Program participants included about 120 11th and 12th graders who were followed from baseline to two weeks and then to six months after the program initiation. About 70 students enrolled in a physics curriculum at a similar school served as a comparison group. The overall sample was about 60% male and 65% white. The program involved instruction regarding the physics of motor vehicle crashes, an evaluation of the safety features of passenger vehicles, a rollover demonstration, and a project in which students aimed to design a "vehicle" that would keep an egg intact during a six-story fall. When compared with students in the control group, program participants experienced an increase in self-reported seatbelt use at both the two-week and the six-month follow-up. This finding suggests that an interactive curriculum may encourage seatbelt use behaviors, at least in the short term, among some adolescent students. Further study is necessary to confirm the effectiveness of this program.

In an evaluation of the effect of seat belt laws on overall fatal injury rates, Houston, Richardson, and Neeley (1996) examined the fatal MVC experience, based on FARS data, for all 50 states between 1975 and 1991. Although this study did not specifically measure outcomes among adolescents, it is a high quality study with interesting results and so warrants mention. After controlling for a myriad of potential confounding factors, including other motor vehicle-related policies, state expenditures for road safety measures, age and income distributions of the state populations, population density, population alcohol consumption, and climate, Houston and colleagues found that seatbelt laws were associated with desirable trends in fatal MVCs. Several findings support this assertion. First, the existence of a seatbelt law in a given state was associated with a significantly lower occurrence of motor vehicle-related fatalities in that state. Second, the effect on the fatality rate was larger in states that allowed primary enforcement, where an individual can be stopped and ticketed simply for violating the seatbelt law, than in states where enforcement was only secondary, meaning that ticketing for violation of the seatbelt law is allowed only if an individual has been pulled over for another reason. Finally, laws that applied to the back seat as well as the front seat were associated with a more sizable decrease in fatal injuries than were laws that applied only to the front seat. Of note, seatbelt laws were associated with an increase in the rate of serious injuries in fatal MVCs. The study authors propose that this effect is likely due to an increase in seatbelt use, which decreases the risk of death in cases of serious injury that, without the use of a seatbelt, would have been fatal. Thus, in serious crashes that could lead to fatality, seatbelt use may prevent death, allowing for survival but with serious injury. Notably, based on a systematic review of the research literature, the Task Force on Community Preventive Services (described above) strongly recommends the implementation of seat belt laws-accompanied by rigorous, primary enforcement of these laws-as an effective approach to increase seatbelt use (Dinh-Zarr, et al., 2001; see also Task Force on Community Preventive Services, 2001).