Impact of the dry law on road traffic mortality in brazilian states: An interrupted time series analysis

Objective: To assess the impact of 2008 Public Law number 11,705, also known as Dry Law (DL-08), on mortality from road traffic accidents (RTA), in each of the 27 Brazilian Federative Units (BFUs). Methods: Ecological study of interrupted time series with RTA data from 2002 to 2015, totalizing 168 months. Data were obtained from the Mortality Information System, the Brazilian Institute of Geography and Statistics, and from the National Traffic Department. Autoregressive integrated moving average (ARIMA) models were adjusted to assess the impact of DL-08 in each BFUs. Results: After the implementation of the DL-08, there was a significant decrease in mortality from RTA in the state of Santa Catarina (pre DL-08 = 2.60 ± 0.30 and post DL-08 = 2.32 ± 0.35; p < 0.001) and in the Federal District (pre DL-08 = 2.22 ± 0.40 and post DL-08 = 1.76 ± 0.35; p = 0.002), a significant increase in mortality in the states of Acre, Amazonas, Rondônia, Maranhão, Piauí, Ceará, Rio Grande do Norte, Paraíba, Pernambuco, Alagoas, Sergipe and Mato Grosso, and a stability in the other states. The sensitivity analysis conducted over a shorter time series with 24 months showed results similar to those obtained with the 168-month series for most of the 27 BFUs. Conclusion: The DL-08 had a heterogeneous impact on mortality from traffic accidents on BFUs.