New wrinkle in pot debate: stoned driving

By KRISTEN WYATT , Associated Press
In this photo taken on Tuesday, March 6, 2012, Angeline Chilton a suburban Denver woman with multiple sclerosis who smokes pot twice a day to ease tremors, holds her pipe as she sits on the front porch of her home in Lakewood, Colo. Chilton insists that she never drives high, but she fears that officials will rush to set an unproven blood-level standard that would put her at risk of breaking the law. In Colorado and Washington, the debate over how to tell whether a driver is high is more than academic. The states are struggling to come up with a blood-level standard for marijuana that would be analogous to the blood-alcohol standard used to decide who's driving drunk. (AP Photo/Ed Andrieski)

(AP) -- Angeline Chilton says she can't drive unless she smokes pot. The suburban Denver woman uses medical marijuana to ease multiple sclerosis symptoms and says she'd never get behind the wheel right after smoking. But her case underscores a problem that no one's sure how to solve: How do you tell if someone is too stoned to drive?

States that allow medical have grappled with determining impairment levels for years. And voters in Colorado and Washington state will decide this fall whether to legalize the drug for recreational use, bringing a new urgency to the issue.

A Denver marijuana advocate says officials are scrambling for limits in part because more drivers acknowledge using the drug.

"The explosion of patients has led to a lot of drivers sticking the (marijuana) card in law enforcement's face, saying, `You can't do anything to me, I'm legal,'" said Sean McAllister, a lawyer who defends people charged with driving under the influence of marijuana.

It's not that simple. Driving while impaired by any drug is illegal in all states.

But it highlights the challenges law enforcement officers face using old tools to try to fix a new problem. Most convictions for drugged driving now are based on police observations, followed later by a .

Authorities envision a legal threshold for pot that would be comparable to the blood-alcohol standard used to determine drunken driving.

But unlike alcohol, marijuana stays in the blood long after the high wears off a few hours after use, and there is no quick test to determine someone's level of impairment - not that scientists haven't been working on it.

Dr. Marilyn Huestis of the National Institute on Drug Abuse, a government research lab, says that soon there will be a to detect recent marijuana use.

But government officials say that doesn't address the question of impairment.

"I'll be dead - and so will lots of other people - from old age, before we know the impairment levels" for marijuana and other drugs, said White House drug czar Gil Kerlikowske.

Authorities recognize the need for a solution. Marijuana causes dizziness, slowed reaction time and drivers are more likely to drift and swerve while they're high.

Dr. Bob DuPont, president of the Institute for Behavior and Health, a non-government institute that works to reduce drug abuse, says research proves "the terrible carnage out there on the roads caused by marijuana."

One recent review of several studies of pot smoking and car accidents suggested that driving after smoking marijuana might almost double the risk of being in a serious or fatal crash.

And a recent nationwide census of fatal traffic accidents showed that while deadly crashes have declined in recent years, the percentage of mortally wounded drivers who later tested positive for drugs rose 18 percent between 2005 and 2011.

DuPont, drug czar for Presidents Richard Nixon and Gerald Ford, wrote a paper last year on drugged driving for the Obama administration, which has made the issue a priority.

Physicians say that while many tests can show whether someone has recently used pot, it's more difficult to pinpoint impairment at any certain time.

Urine and blood tests are better at showing whether someone used the drug in the past - which is why employers and probation officers use them. But determining current impairment is far trickier.

"There's no sure answer to that question," said Dr. Guohua Li, a Columbia University researcher who reviewed marijuana use and motor vehicle crashes last year.

His survey linked pot use to crash risk, but pointed out wide research gaps. Scientists do not have conclusive data to link marijuana dosing to accident likelihood; whether it matters if the drug is smoked or eaten; or how pot interacts with other drugs.

The limited data has prompted a furious debate.

Proposed solutions include setting limits on the amount of the main psychoactive chemical in marijuana, THC, that drivers can have in their blood. But THC limits to determine impairment are not widely agreed upon.

Two states place the standard at 2 nanograms per milliliter of blood. Others have zero tolerance policies. And Colorado and Washington state are debating a threshold of 5 nanograms.

Such an attempt failed the Colorado Legislature last year, amid opposition from Republicans and Democrats. State officials then set up a task force to settle the question - and the panel couldn't agree.

This year, Colorado lawmakers are debating a similar measure, but its sponsors concede they don't know whether the "driving while high" bill will pass.

In Washington state, the ballot measure on marijuana legalization includes a 5 nanogram THC limit.

The measure's backers say polling indicates such a driving limit could be crucial to winning public support for legalization.

"Voters were very concerned about impaired driving," said Alison Holcomb, campaign director for Washington's legalization measure.

Holcomb also pointed to a failed marijuana legalization proposal in California two years ago that did not include a driving THC limit.

The White House, which has a goal of reducing drugged driving by 10 percent in the next three years, wants states to set a blood-level standard upon which to base convictions, but has not said what that limit should be.

Administration officials insist marijuana should remain illegal, and Kerlikowske called it a "bogus argument" to say any legal level of THC in a driver is safe.

But several factors can skew THC blood tests, including age, gender, weight and frequency of marijuana use. Also, THC can remain in the system weeks after a user sobers up, leading to the anxiety shared by many in the 16 medical marijuana states: They could be at risk for a positive test at any time, whether they had recently used the drug or not.

A Colorado state forensic toxicologist testified recently that "5 nanograms is more than fair" to determine intoxication. But, for now the blood test proposals remain politically fraught, with supporters and opponents of marijuana legalization hinging support on the issue.

Huestis, of the government-funded drug abuse institute, says an easy-to-use roadside saliva test that can determine recent marijuana use - as opposed to long-ago pot use - is in final testing stages and will be ready for police use soon.

Researchers envision a day when marijuana tests are as common in police cars as Breathalyzers.

Until then, lawmakers will consider measures such as Colorado's marijuana DUI proposal, which marijuana activists say imperils drivers who frequently use the drug such as Chilton, the patient.

Chilton says she smokes medical marijuana twice a day to ease tremors caused by the condition that left her homebound for years.

She says that since she began using pot she has started driving again and for the first time in five years has landed a job.

Chilton worries Colorado's proposal jeopardizes her newfound freedom.

"I don't drink and drive, and I don't smoke and drive," she said. "But my body is completely saturated with THC."

More information: National Institute on Drug Abuse drugged driving report: http://goo.gl/ZAYwn

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ormondotvos
not rated yet Mar 18, 2012
Add to the confusion with the news that CBD (cannabidiol) has strong medical effects and weak psychoactivity. Cannabis growers are now breeding CBD-enriched strains that give medical relief without causing undesirable "highs". What happens when THC is bred out of the cannabis?

Kerlikowske will cost Obama California this year. There are a LOT of cannabis users on medical prescriptions, and their friends. If Obama loses California, goodbye good stuff.
Wolf358
not rated yet Mar 19, 2012
Years ago, the State of Washington researched the effects of marijuana on driving errors, compared to alcohol and a placebo. (Have they forgotten? It was in Scientific American.)
Their research showed that for the first hour and a half, the marijuana driver makes _less_ driving errors than the _placebo_ driver.
Houston, we have a problem...
baudrunner
not rated yet Mar 19, 2012
Accurate testing for blood/alcohol levels are only possible when an actual blood sample is analysed. Breathlizer testing for alcohol is inadmissable in the courts of South Dakota, because of the inherent innacuracy of breath samples from different individuals who metabolize alcohol differently, at different levels of efficiency. Pot testing is even more problematic, considering that there are any number of cannabinoid compounds in pot, of which THC is just one. Pot signs can actually stay in your system for up to 6 months. A user who hasn't smoked for weeks can still test positive. The only solution is legalization. As for driving factors, I've always been of the opinion that when you hits the road, you takes your chances.
alfie_null
not rated yet Mar 25, 2012
The focus should be on making use of automobiles safer. In that context, how does the hazard of marijuana intoxication compare to use of cell phones, fiddling with dashboard controls, being sleepy, worrying about something, talking with passengers, or all the other possible ways driving ability can be degraded?
I'm looking forward to when google (or whomever) produces a driverless car.