Perceived risk of arrest is among the biggest deterrents to drunk driving, according to researchers who said that having laws on the books alone is not sufficient to deter those at high risk of driving under the influence of alcohol.

Researchers from the University of Missouri and the University of Georgia said that while the number of drunk-driving arrests in a state has little relationship to the likelihood of drunk driving occurring, perceptions about the risk of arrest can be a deterrent.

"Essentially, law enforcement needs to focus on perceptions; it is important that drivers perceive that they will be caught if they drive impaired," said Lilliard Richardson, professor in the University of Michigan's Truman School of Public Affairs. "We found that high-risk drivers are less likely to drink and drive if they perceive they are likely to be stopped or arrested by police. However, the mere existence of laws designed to discourage people from drinking and driving does not impact high-risk drivers.

"The results provide support for the value of high-visibility enforcement campaigns," continued Richardson. "Public-safety education and media efforts are important components of the overall strategy for reducing impaired driving."

Individuals who agreed with the goals of deterrence laws also were less likely to drink and drive, the study said.

The researchers based their conclusions on interviews conducted as part of the National Highway Traffic Safety Administration's 2001 National Survey of Drinking and Driving Attitudes and Behavior.

The study, "The Behavioral Impact of Drinking and Driving Laws," was published in the November 2008 issue of the Policy Studies Journal.