A small group of volunteers spent much of the last year getting drunk and stoned on marijuana furnished by the federal government before getting behind the wheel.
The volunteers were part of what federal scientists say was the most comprehensive study ever conducted on how marijuana, and pot combined with alcohol, affect drivers. The data now being analyzed ultimately will help regulators decide how stoned is too stoned to drive. It’s similar to the studies conducted to develop levels for drunken driving. Volunteers were recruited from around Iowa City, home to the University of Iowa’s National Advanced Driving Simulator.
“They were happy to participate,” said Dr. Marilyn Huestis, chief of chemistry and drug metabolism at the Intramural Research Program at the National Institute on Drug Abuse.
The participants never got on real roads. Instead, they drove for about 40 minutes behind the wheel of NADS, a federally funded simulator that can mimic the look and feel of everything from urban parking lots to darkened gravel roads. Deer jump out unexpectedly. Passing cars swerve.
Before getting behind the NADS wheel, each volunteer was required to consume specific combinations of marijuana and alcohol or a placebo. Because the university has a smoke-free campus, the volunteers had to use a vaporizer to consume their marijuana, which was furnished under strict rules by a federal garden at the University of Mississippi.
Each of the 19 drivers who completed the six combinations of pot and alcohol gave blood and saliva tests during their drives to check intoxication levels, said Huestis, who says the entire experiment took three years to design and administer.
The testing finished this spring, and now scientists are studying the 250 variables checked by the tests. They hope to have initial data available by October.
“In this country, there’s a huge controversy over whether there should be zero tolerance or there should be some level that’s acceptable. It’s a terribly difficult problem,” Huestis said. “We will be looking at what are the kinds of functions that are affected and whether they are significantly different … whether alcohol is on board or not.”
Colorado State Trooper J.J. Wolff has made a career of tracking down intoxicated and drugged drivers. As one of the state’s leading experts in identifying impaired drivers, Wolff knows many Americans are watching what’s happening on Colorado roads.
“I have personally not seen more stoned drivers, not arrested more stoned drivers,” says Wolff. “From my point of view, that’s good.”
To check whether drivers might be impaired by alcohol, marijuana or prescription drugs, Wolff puts them through a series of voluntary roadside tests.
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