(April 25, 2009)-- Zero tolerance policies on underage drinking have zero effect on teenage drinking and driving, Sam Houston University Assistant Professor of Economics Darren Grant says in a study titled, “Dead on Arrival: Zero Tolerance Laws Don’t Work.”

Grant analyzed data on nearly 30,000 fatalities in nighttime accidents nationwide that involved drivers less than 21, using data from the Department of Transportation and other data from laws and all 50 states, the university said.

“The empirical work showed consistently that these laws had no effect,” Grant said.

“If you look at the total number of accidents or the types of drinkers involved in these accidents, they just aren’t affected. Other factors matter, but not these laws.”

Zero tolerance laws appeared on the books during the 1990s, when Congress threatened to withhold federal highway funds from states that didn’t comply.

“The idea was, since drivers under 21 are not supposed to be drinking, you should be guilty of drunk driving if you are caught driving with any amount of alcohol in your system,” Grant said.

The problem, Grant said, is that zero tolerance laws “don’t change the penalties for drunk driving, only the legal blood alcohol limit.

“It’s not making the penalty for drunk driving harsher,” he said.

“It is just harder to satisfy the law. Drivers now have to give up drinking all together. It’s more exacting in that sense.

“Because you must sacrifice more to comply with the law, we should expect two responses: some people will comply and drink less, but others will just give up trying to satisfy the law and drink more,” he said.

“So we should not assume a zero tolerance law will inevitably reduce drunk driving.”

“I expected to see more heavy drinkers and also more non-drinkers, but I didn’t,” he said. “Instead, among drivers involved in traffic accidents, there is the same fraction of heavy drinkers, the same fraction of mild drinkers, the same fraction of nondrinkers. It’s just not changing.”

The study is scheduled for publication within the next year in the journal Economic Inquiry, the university said.