Health insurance mandates and traffic fatalities: The effect of substance use disorder parity laws

We investigate whether state-specific health insurance parity laws for substance use disorder (SUD) treatment reduce traffic fatalities. Parity laws compel private insurers to cover SUD treatment more generously. We employ 26 years of administrative data from the Fatality Analysis Reporting System coupled with a differences-in-differences design to study this question. Our findings indicate that passage of a parity law is associated with a 7.6 to 8.2% reduction in traffic fatality rates. These findings suggest that government regulations requiring insurers to cover SUD treatment can significantly improve traffic safety, possibly by reducing the number of impaired drivers on roadways.