A study by public health researchers at NYU’s Steinhardt School of Culture, Education, and Human Development finds that the severity of the drunk drive problem within the state is not the most important predictor of whether states adopt new laws to restrict drunk driving – nor is the political makeup of the state government. Instead, the two strongest predictors of states adopting their first drunk driving laws were having a large population of young people and a neighbouring state with similar driving laws. The findings, published in the American Journal of Public Health, suggest that state lawmakers look at factors both within their states as well their neighbouring states when considering new driving laws. In the study, the researchers looked at seven statewide laws on alcohol-impaired driving adopted between 1980 and 2010: a 0.08 limit on blood alcohol content; a ban on open alcohol containers; zero tolerance laws for drivers under the age of 21; and license suspension, minimum fines, mandatory community service, and minimum prison time for driving under the influence. The researchers analysed each state’s adoption of the laws from 1980 to 2010 to identify predictors of first-time and subsequent law adoption. They then compared the adoption of these laws to both internal and external state factors. Internal factors included the political environment, state resources, legislative history, population characteristics, unemployment rate, alcohol consumption per person, taxes, and traffic fatality rates. External factors measured were the neighbouring states’ history of law adoption and changes in federal law. The authors found that neighboring states’ adoption of laws was quite influential, as was the state’s own history of prior law adoption. Contrary to expectations, the political makeup of the state’s government was not predictive of greater regulation.