The Associated Press

BOSTON Reckless drivers who don't seem drunk may well be high on cocaine or marijuana, according to roadside tests that indicate drugs may rival alcohol as a hazard on the highway.

Police in Memphis, Tenn., gave urine tests to reckless drivers who appeared not to be drunk. They found that more than half were on cocaine or marijuana.

"It was a surprise that so many were under the influence of drugs, although we suspected there would be a significant number," said police Inspector Charles S. Cook.

Police routinely give breath tests to bad drivers whom they suspect to be drunk. However, on-the-spot testing for other drugs is rare, since it requires taking a urine specimen something that is not practical on the highway.

For an experiment in roadside drug testing, Memphis police put together a "drug van," a former ambulance fitted out with toilet, interview area and videotaping equipment.

In the summer of 1993, they gave drug tests on the spot to any reckless drivers who were not obviously drunk. Police took urine samples from 150 drivers, and 89 of them, or 59 percent, tested positive for cocaine or marijuana.

The tests, widely available from several manufacturers, can give results in 10 minutes. The standard for a positive test was the same as that used by the federal government to measure recent drug use in the workplace.

While a positive result often means people have taken drugs in recent hours, those who regularly use very high amounts of cocaine or marijuana may flunk the tests even though they have been off drugs for days.

The results of the police experiment were written for Thursday's issue of the New England Journal of Medicine by Dr. Daniel Brookoff of Methodist Hospital in Memphis.

Brookoff said he decided to get involved in the issue of drugged driving after a man hit a friend's two daughters while driving on the wrong side of the road. The man was never tested for drugs, but Brookoff believes he was high on marijuana.

"The reality is, we think it's as big a problem, or maybe bigger, as drunk driving," said Brookoff.

Police can often tell when drivers are drunk even before they give the breath test. But drugged driving is much harder to detect, because there is no clear pattern of appearance. For instance, drivers on cocaine may act sleepy and slow, happy and talkative or combative and paranoid.

When asked to take the standard curbside sobriety test, which involves measuring coordination and attention, cocaine drivers can actually perform better than sober folks.

"We saw people who did great on the sobriety test," said Brookoff. "The problem was, they were driving 90 miles an hour on the wrong side of the road with their lights off."

He said cocaine drivers were often glad to take the drug test, certain they would pass. They show poor judgment on the road, too. Typically they are wildly overconfident of their abilities, taking turns too fast or weaving through traffic.

"Diagonal driving," Cook calls this. "They are just as involved in changing lanes as in going forward."

The effects of cocaine can last for days. Those withdrawing from the drug may drive worse than people who are still high.

Cook said drivers on marijuana can be inattentive and have poor reflexes. In this way, they are similar to drunks, although their impairment is usually less extreme.

While the study was going on, Memphis police made 111 arrests for driving under the influence of drugs. During the same period in 1992, they made only six arrests, five of them after serious accidents.

Cook said Memphis police continue to use the drug van. Read Next Article