An investigation of state population characteristics that moderate the relationship of state seat belt law and use in the United States.

Objectives Primary enforcement laws have been shown to be effective methods for increasing seat belt use at the state level. Method This study investigates state differences in the effectiveness of primary enforcement laws by assessing whether a state's academic achievement, health ranking, economic prosperity, violent crime rates, government effectiveness, gender distribution, or proportion of rural roads moderate the relationship between those laws and seat belt compliance rates. Results Aggregate state-level academic achievement, health ranking, government effectiveness, and proportion of rural roads uniquely moderated the seat belt use differences between primary and secondary enforcement states. Conclusions This evidence suggests that cultural, social, and demographic differences among regions may be important factors in explaining state-level differences in the effectiveness of primary enforcement of seat belt laws. [ABSTRACT FROM AUTHOR]