Zero-tolerance Drinking and Driving Laws: Effectiveness Tested

Are zero-tolerance drinking and driving laws effective in reducing traffic deaths? Brazil implemented a zero tolerance traffic law in 2008. Researchers examined the impact of this law in two time series. The first was 1980 to 2007. The second was 2008 to 2013.

Data on both traffic mortality and population came from an official source. It was the Brazilian Ministry of Health. Researchers separately analyzed the results of zero-tolerance in three of the major capitals in Brazil. They were Rio de Janeiro, Belo Horizonte, and Sao Paulo.

There were no changes in the traffic fatality rates before and after the law in two cities. Those were Rio de Janeiro and Belo Horizonte. However, after the law was adopted the rate jumped in Sao Paulo. Significantly, it had been declining there before the new law.

zero-tolerance drinking and drivingThe researchers concluded that the zero-tolerance law clearly did not reduce alcohol-related traffic fatalities.

This demonstrates that apparently simple solutions to complex problems may not be effective. Many other ‘common sense’ policies are also ineffective. An example is applying more severe punishment for those who drive while intoxicated. That may seem reasonable. However, it’s the perception of  certainty rather than severity of punishment that has a deterrent effect on DUI.

Similarly, increasing the cost of alcohol with increased taxation might seem helpful. But that has virtually no impact on reducing drunk driving. Heavy drinkers cause most traffic deaths. And higher costs don’t deter them. In addition, most minors who drink don’t buy their beverages.

Nor is popularity of a program associated with effectiveness. Drug Abuse Resistance Education (DARE) is very popular. Yet research finds it ineffective. Even worse, it’s sometimes even counterproductive.


It appears that zero-tolerance drinking and driving laws are probably ineffective.

Source: Volpe, F., et al. Evaluating the Brazilian zero-tolerance drinking and driving law. Time series analyses of traffic-related mortality in three major cities. Traf Inj Prev, 2017, 18(4), 337-343.

Popular Resources on Zero Tolerance

Not all of these resources are about zero-tolerance drinking and driving laws. But all concern the effectiveness of zero-tolerance.

Ayers, W., et al.  Zero Tolerance. Resisting the Drive for Punishment in our Schools.  A Handbook for Parents, Students, Educators, and Citizens. NY: New Press, 2002.

Bratton, W., et al. Zero Tolerance. Policing a Free Society. London: IEA Health and Welfare Unit, 1998.

Hoopla Digital. Zero Tolerance. Hoopla Digital, 2015.

Illinois Secretary of State. DUI, Zero Tolerance & Related DUI Offenses. Springfield: The Secretary, 2015

National Highway Traffic Safety Administration. Zero Tolerance for Youth. Four States’ Experience with Zero Tolerance Laws. Washington: The Administration, 2000.

Wachtel, T., et al.  Beyond Zero Tolerance. Restorative Practices in Schools. Bethlehem, PA: Int Inst Restorative Prac, 2012. (Video)