Seatbelt laws and seatbelt use among front- and rear-seat vehicle occupants in fatal crashes in the United States

Abstract

Seatbelt laws are deemed effective at increasing seatbelt use, consequently, reducing fatalities associated with motor vehicle crashes in the United States. Previous studies have provided significant insights about the effectiveness of seatbelt laws, however, studies exploring passenger seatbelt use accounting for the variations in seatbelt laws are not well documented in the literature. Seatbelt laws vary by whether they cover front-seat occupants only or include rear-seat passengers as well. The primary objective of this study was to investigate the differences in adult seatbelt compliance rate based on six categories of seatbelt laws in the United States using crash data. In this present study, six categories of seatbelt laws are considered ranging from no seatbelt law to primary seatbelt law covering all vehicle occupants. Using Tukey-type multiple comparison test, a positive relationship between seatbelt laws and adult seatbelt use was found. Specifically, states with stricter seatbelt laws, that is primary law for all front- and rear-seat occupants, exhibit higher seatbelt compliance rate than those with less strict (partial primary/secondary laws) or no seatbelt laws. Given the significant differences in adult seatbelt use based on our study design (using six categories of seatbelt laws), the analysis support that if states upgrade their seatbelt laws from no/secondary laws to primary laws covering all vehicle occupants, there likely will be positive impacts on adult seatbelt use. The findings in this study are to inform and support decision policies and intervention strategies that are effective at promoting safety for motor vehicle occupants.