Abstract

Background: In April 2016, Chile enacted the Law 20,900, which restricted electoral publicity on public roads. It established two important regulations: first, candidates were allowed, 30 days before any election, to publicize their campaigns in specific street locations. Second, roadside publicity must follow strict size standards to avoid visual contamination. This article examines the impact of this regulation in reducing road traffic crashes. Methods: We obtained a number of traffic injuries and fatalities per population from public records. A time-series difference-in-difference study, using generalized linear models with an interaction between time-period and intervention, compared a municipal election period before the introduction of Law 20,900 (2012) to the first municipal election affected by the law (2016). We adjusted for precipitation and temperature, and applied models to three cities: Santiago, Gran-Valparaiso, and Concepcion. We assessed the overall impact of the intervention using random effects meta-analyses. Results: The law was associated with a decrease of 0.01 (95% confidence interval [CI]: -0.02, -0.00) in Santiago, a decrease of 0.01 (95% CI: -0.03, -0.00) in Valparaiso and an increase of 0.09 (95% CI: 0.06, 0.13) in Concepcion, in all daily injuries and fatalities per 100,000 population. After 40 days of its implementation, the intervention was associated with a mild absolute reduction of 34 (95% reduction interval: -270, 67) traffic injuries and fatalities. Conclusions: This study estimates that the regulation of public road publicity had an overall mild effect on reducing traffic injuries and fatalities in three large cities in Chile.