Reducing the legal blood alcohol concentration limit for driving in developing countries: A time for change? Results and implications derived from a time-series analysis (2001-10) conducted in Brazil

Aims In Brazil, a new law introduced in 2008 has lowered the blood alcohol concentration limit for drivers from 0.06 to 0.02, but the effectiveness in reducing traffic accidents remains uncertain. This study evaluated the effects of this enactment on road traffic injuries and fatalities. Design Time-series analysis using autoregressive integrated moving average (ARIMA) modelling. Setting State and capital of São Paulo, Brazil. Participants A total of 1471087 non-fatal and 51561 fatal road traffic accident cases in both regions. Measurements Monthly rates of traffic injuries and fatalities per 100000 inhabitants from January 2001 to June 2010. Findings The new traffic law was responsible for significant reductions in traffic injury and fatality rates in both localities (P<0.05). A stronger effect was observed for traffic fatality (-7.2 and -16.0% in the average monthly rate in the State and capital, respectively) compared to traffic injury rates (-1.8 and -2.3% in the State and capital, respectively). Conclusions Lowering the blood alcohol concentration limit in Brazil had a greater impact on traffic fatalities than injuries, with a higher effect in the capital, where presumably the police enforcement was enhanced.