Staunch opponents of drunk driving may rethink their position after a few drinks, a new study has found. After comparing data collected from 82 young adults, the researchers determined that subjects’ willingness to drive intoxicated changed significantly after moderate amounts of alcohol. The findings reinforce the idea that safe driving practices – such as designated drivers – should be considered before the first drink.

While attitudinal shifts during alcohol consumption are nothing new, the researchers were jarred by their magnitude. Denis McCarthy, an associate professor of psychology, said that when it came to driving intoxicated, the disparity of opinion was very alarming.

"We all probably know people who make good decisions about lots of things when they're sober, but put four or five beers in them and they make bad ones. So that part wasn't surprising," McCarthy said, speaking to HealthDay. "I was surprised, however, that it was such a big effect over and above their sober beliefs."

For the experiment, researchers enrolled 43 men and 39 women in two laboratory sessions. During the first session, participants were given a moderate amount of alcohol and asked to offer their take on drunk driving. They also rated their willingness to drive “right now.” At various points throughout the analysis, the researchers measured their breath alcohol concentration (BrAC).

In the second session, the participants were asked to evaluate the dangers of driving at hypothetical BrAC values provided by the researchers.

Compared to their sober assessments, the subjects’ drunken appraisals tended to underplay the dangers of driving at relatively high BrAC values. This disparity was particularly pronounced at BrAC levels following a subject’s peak value. As the alcohol began to wear off, subjects felt more sober than they actually were.

"It's a good thing to keep in mind that your judgment when intoxicated is going to be different than your judgment the rest of the time," McCarthy explained. "We showed that there are bigger effects on the descending limb of the BrAC curve, which is important because that's when people are typically driving home. People on the way down [the BrAC curve] later in the evening are worse judges of how impaired they are, and they're more impaired than they think."

According to the U.S. Centers for Disease Control and Prevention, almost 30 people in U.S. die in alcohol-related motor vehicle accidents every day. The crashes cost society more than $51 billion annually. McCarthy and his team hope that their findings will help lower these statistics by formalizing the decline in judgment that alcohol necessarily brings about.