The paper by Pechansky & Chandran on driving while intoxicated (DWI) in South America provides a nice review of the status of the control and prevention of DWI in Brazil, or lack thereof, also calling attention to the fact that a similar worrisome situation is probably present in most other Latin American countries . The picture described in the paper is classical of many Latin countries: regulations are developed and voted into law by legislative bodies but never enforced, or enforced inconsistently. As a result, offenses continue and the problem remains unabated or even grows. In Brazil, DWI-related laws are not the only ones that are ignored. Having lived in that country for the first 28 years of my life, I experienced first hand the Brazilian phenomenon of laws that ‘did not catch’; in Portuguese: a lei não pegou.
I agree with Pechansky & Chandran that the picture of DWI prevention is more positive in North American countries than in South America. Little by little, over the past 30 years, most states in the United States adopted a comprehensive set of DWI-related legislation that is well enforced and effective in preventing DWI. However, let us not forget that it has only been since the beginning of the 1980s that popular sentiment about DWI in the United States began to change from tolerance to seeing it as a clearly unacceptable behavior. The switch in public attitude was accompanied by the enactment of new laws and increased enforcement. Much of this switch in public sentiment was due to the unwavering work of Mothers Against Drunk Driving (MADD). This group of mainly victims of DWI has been a tremendous force for change in US cultural views about DWI.
In the United States, the work carried out by MADD, by public health professionals, by the law enforcement community and communities across the country in the past 30 years has led to a reduction in DWI. Alcohol-related traffic fatalities [blood alcohol concentration (BAC) 0.08+] declined from a high rate of 59.5% in 1982 to 39.7% in 1999 as a proportion of all traffic fatalities, and then stabilized . In 2009, the last year for which data are available, there were 10 839 alcohol-related traffic fatalities in the United States, or 32% of all traffic fatalities . The latest US roadside survey of 2007 showed that 2.2% of weekend night-time drivers had a BAC of 0.08 or higher, a decrease from 7.5% in 1973 . However, alcohol is not the only problem. Based on both blood tests and oral fluid results collected from drivers during the survey, 16.3% of night-time drivers tested drug-positive.
However, in spite of these reductions, DWI remains a highly prevalent behavior among adults in the United States. Among US Hispanics, for instance, who now comprise 16% of the US population  and come from the countries discussed by Pechansky & Chandran, the 12-month rate of self-reported DWI is 17% among Mexican Americans, 14.5% among South/Central Americans, 7.8% among Puerto Ricans and 6.2% among Cuban Americans. Rates are lower among women, ranging from 7.5% for Mexican Americans to 1.1% for Cuban Americans . Curiously, it is not the Latin immigrant who comes to the United States from countries with lax attitudes about DWI that is most likely to engage in this behavior. US-born Hispanics are about 1.7 times more likely than Hispanic immigrants to report DWI in the past 12 months , most probably because of greater affluence and increased access to cars. Finally, using 1973 data, Beitel et al.  estimated that the probability of an arrest for DWI among drivers with a BAC 0.10 or higher was one in 200. Nowadays, this probability may have decreased a little, but not greatly. To bring this probability close to the level of self-reported DWI in the adult population, as exemplified with US Hispanics above, will require resources that realistically will not be available in the foreseeable future. This indicates strongly that DWI must be prevented by an increased and continuous change in public attitudes and behavior.
So, can the US experience of the past 30 years provide any suggestion and hope to public health professionals concerned with DWI in Latin American countries, especially Brazil? I think so, and it is a message of optimism. If the grass looks greener on the Anglophone northern side of the equator, it is important to remember that it has not always looked this green. In other words, there is nothing inherently special about US and Canadian cultures that allows these two countries to have effective strategies to address DWI, except perhaps that they have more advanced economic development and, thus, more resources. By the same token, there is nothing inherently special about Latin culture that prevents the same DWI preventive actions from being implemented and enforced South of the Equator. Brazil, for instance, may have a long way to go to reach the same level of law enforcement against DWI seen in the United States and Canada, but it has already started to move in the right direction. Enactment of the ‘dry law’ described by Pechansky & Chandran is a good example. Another is the growing preoccupation about DWI by a group of Brazilian public health professionals, which is well exemplified by Pechansky & Chandran's paper. Working with communities, non-governmental organizations and advocacy groups is also very important. Without community support and awareness, DWI prevention and control will be much more difficult, if not impossible.