Carnevali, R (Carnevali, Raul).Univ Talca, Ctr Estudios Derecho Penal, Fac Ciencias Jurid & Sociales, Santiago, ChileChile has recently entered into force Act No. 20.580, which modifies the legal limits of blood alcohol concentration in drivers and increases the penalties for driving under the influence of alcohol, narcotics or psychotropic substances. The aim of this review was to give an account of the strengths of this new law but, at the same time, to alert the scientific and legal community about its flaws. We also present some shortcomings of Chilean regulatory framework that remain uncorrected, those that should be considered in the design of public policies for improving road safety and the criteria that judges should ponder during judgment, to determine either conviction or acquittal. (Rev Med Chile 2012; 140: 939-945).