Effectiveness of a new law to reduce the legal blood alcohol concentration (BAC) limit for
driving in Chile
Author(s): Beatriz Nistal-Nuño MD, Walker R. MD, Mcmillan A. PhD
Institute(s): Stanford University Medical Center, Emergency Medicine, Stanford, United States.
Text: 
Background: Traffic accidents are one of the most important public health problems in the world and produce social, work and human resources losses. In Chile, a new law introduced in March 2012 has lowered the blood alcohol concentration limit for impaired drivers from 0.1% to 0.08% and the blood alcohol limit for driving under the influence of alcohol from 0.05% to 0.03%, but the effectiveness in reducing traffic accidents remains uncertain.The main goal of this investigation is to evaluate the effects of this enactment on road traffic injuries and fatalities in Chile.This represents the first study on the effectiveness of lowering the legal BAC limits in Chile.
Methods: We conducted a preliminary retrospective and prospective review of national databases in Chile from January 2003 until September 2012 to compare the total number of traffic fatalities and injuries and due to alcohol before and after the new road traffic law. We measured monthly rates of traffic injuries and fatalities per 100 000 inhabitants. The data sources included the National Institute of Statistics of Chile, the Ministry of Transport and Telecommunications of Chile (Conaset) and police reports. These databases are available in the public domain. Data were analyzed using SPSS software using a Generalized Linear Models approach, type of Poisson regression, to analyze deaths and injuries.
Results: Using SPSS software with the model Month and Period, the odds ratio for deaths after the law relative to deaths before the law was 0.86 and the effect was significant P< 0.000 (0.86 ± 0.05). Adding a linear trend to the model, Yrs. Lin as a predictor, the rate after the law was only 0.957 ± 0.06 the rate before the law. And that was not significant (P< 0.211).
Conclusion: During the period of January 2012 to September 2012 there was a reduction of 109 deaths in traffic accidents in comparison to the same period in 2011. This figure represents the lowest number of deaths in traffic accidents of the last 16 years. The number of deaths due to alcohol in traffic accidents decreased by 28% during this period compared to 2011. The number of injuries due to alcohol in traffic accidents decreased by 30% during the same period compared to 2011.The information obtained in the present study may help to generate preventive strategies to control deaths and injuries caused by traffic accidents due to alcohol. Our sample size and postlaw data was not sufficient to detect significant relevant differences.

Effectiveness of a new law to reduce the legal blood alcohol concentration (BAC) limit for driving in Chile