Increasing Seatbelt Use Through Legislation and Enforcement

Seatbelts are widely reported as one of the most effective interventions for reducing road traffic fatalities and injuries. Some researchers have identified that wearing a seatbelt can decrease an individual’s likelihood of serious injury by 23% to 33% (Crash Modification Factor 0.77 to 0.67) and their likelihood of death by 45% to 55% (CMF 0.55 to 0.45) (World_Health_Organization 2009).
Since some drivers do not comply, the overall effect on fatalities and injuries is a reduction of about 11% (CMF 0.89) in high-income countries. Given the strong evidence for the technical effectiveness of seatbelts, many countries across the
world have implemented mandatory seatbelt laws for the occupants of passengers and light trucks. The adoption of these laws is significantly lower in low and middle income countries (LMICs) compared to high-income countries (HICs), meaning a larger proportion of the population in LMICs do not wear a seatbelt (World_Health_Organization 2013).
The best-available information on the effects of changes in seatbelt legislation and seatbelt enforcement, respectively, are presented in this report. These values are recommended for use in the Road Safety Calculator. There is a shortage of information on the effects of seatbelt legislation on non-fatal injury crashes, but the limited results suggest that the CMFs are similar to those for fatal crashes.
This intervention is highly dependent on enforcement. The research on this topic is dominated by studies high-income countries, especially the United States. The limited information from low and middle-income countries suggests an attenuation of crash reduction benefits, probably due to lower levels of enforcement. The U.S. data show indicate that primary enforcement is necessary
to obtain the full benefits of seatbelt legislation.
Since the majority of the research is from the U.S. where about 85% of the traffic is automobiles and light trucks, the Road Safety Calculator will need to incorporate adjustments to account for differing mode shares in other counties, such as the extensive use of motorcycles in Southeast Asia. One potential method is to adjust the CMFs based on the HIC mode share for automobiles and light trucks, and then apply the intervention in the Road Safety Calculator only for each country’s crashes involving motor vehicle occupants.