Effects of Motorcycle Helmet Laws on Fatalities’ Prevention: An Impact Evaluation

Simultaneity bias complicates the estimation of the causal effect of motorcycle helmet usage on fatalities. We overcome this obstacle by exploiting an exogenous variation in the enforcement of the motorcycle helmet usage law between two municipalities in Uruguay. We show evidence of a dramatic increase in helmet usage in one municipality after the law was enforced. In just one month, usage increased from less than 10% to more than 90%. Our difference in difference estimates show that helmet usage laws are associated with a significant decrease in injuries and fatalities