Legal pot presents questions about drugged driving

A macro shot of isolated marijuana / iStockphoto

(CBS News) DENVER - Angeline Chilton says she can't drive unless she smokes pot.

The suburban Denver woman says she'd never get behind the wheel right after smoking, but she does use medical marijuana twice a day to ease tremors caused by multiple sclerosis that previously left her homebound.

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

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 marijuana 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 medical marijuana 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 blood test.

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 saliva test 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 multiple sclerosis patient.

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.

[Stoned_Still]

WHY OH WHY DON'T PEOPLE FEAR ALCOHOL THE WAY THEY DO POT? ALL THOSE GLARING STATISTICS BUT ALL THEY CAN DO IS COWER IN FEAR AT THE MERE MENTION OF A WEED..PATHETIC.

[NeverLift]

For those of you who think driving while high on pot is just fine: Get your reaction time tested while high, compare that to your normal reaction time. I'm referring to the test using projected street images that a driver would see. See how long it takes you to notice the ball bouncing out from between parked cars, then the child, then your reaction. You will hit her.

I drive competitively -- on road course tracks -- and I can assure you, without trying to be punny, your reaction time will more that triple. I've been in a car driven by a mildly high driver exactly twice, and it scared the Hell out of me. (I'll do 140 in traffic on the track, so I don't scare easily.) On the second occasion, at a red light on a reasonably busy day, the driver didn't notice pedestrians stepping off the curb right at his right fender, and made his turn, almost running them down. No, we were not chatting. He was looking. Didn't react to their stepping off the curb.

One can drive safely with a little wine, a beer. But once you are high enough to feel the effect, you are beyond DUI; you are a killer looking for victims.

I do weed, at home. Never, ever, drive then. My rule is, at least two hours, three if more than mildly high, after the last hit before I'll even consider getting behind the wheel.

Seriously, get you reaction time tested. You'll never drive high again.

[EAR8]

Still safer than the million people talking and texting on their phones well driving! Try to react to the bouncing ball when you are texting.

[Stoned_Still]

You are out of your mind. Meet me on the battlefield of Modern Warfare 3 sometime and we'll see how well my reaction times compare to yours. I call complete BS on your statement regarding alcohol. One beer and I could easily kill you and your family with my car. Don't be so naive. I say texting and all cell phone use is more dangerous to your family's lives than me and my 5 nanograms of thc in my blood system. Get a clue already...

[amerilatino]

Empirical evidence has proven that just because someone has a license to drive, it does not mean he/she is not stupid as a bag of hammers with no handle. People drive drunk, while doing their makeup, while texting, while having s-e-x, too close to other cars, too fast for conditions and under the stupifying influence of their own emotions and ceaseless chatter, why give them yet another chance to f*** up while at the helm of a two-ton missile??

[greennnnnn-2009]

Are you saying that no one currently drives any vehicles in this country after smoking pot?

[ConSense]

Good point, greennnnnnnn - people already drive after smoking, AND, there are already laws on the books for people who drive while impaired. It's long past time to make it legal, tax it, and spend our countries resources battling real crime.

[TruthKnowledgeDOTcom]

Alright, I need to clear some things up.

Angeline Chilton says she can't drive unless she smokes pot. - Yeah I can understand because marijuana doesn't impair you like alcohol does to hurt your driving abilities. In fact, I drive better high of pot than without; it gives you "patience" or curbing your anxiety. Anybody who is too stoned to drive doesn't even feel like driving, you just don't and if so, you are still able to concentrate or focus when driving because your awareness isn't impaired like alcohol, your awareness is HIGHTENED, that's why some people get paranoid when high. They are viewing their awareness as paranoia and most feel it's paranoid since for years and most people they are doing something illegal.

"Marijuana causes dizziness, slowed reaction time and drivers are more likely to drift and swerve while they're high." - No that is what happens when you are drunk, not high. Again, being high is more like having a sugar high than being drunk. However, instead of bouncing off walls via ADHD, you are really relaxed! Just so much lies in this article because the risks of crashes are not doubled, they are reduced. How do we know the drug use via 18 percent is marijuana? Alcohol is a drug. I'll just say that whenever I've been high driving, I'm frustrated with the wreck less impatient drivers and I just pull over and let them go by because I'm tired of people riding my ass! I mean I WISH more people were high driving.

"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."

check out my website and join me on facebook!

truthknowledge.com

[NeverLift]

You just think you drive better because you don't even notice your screw-ups. Please, if you are going to drive high, let me know when so I can stay home.

I smoke. Never drive even a touch high. But see my longer essay. I'd make the penalty for driving high at least as severe as DUI, maybe more so.

[Stoned_Still]

NeverLift is still an idiot.

[JDarren]

Driving while high is nowhere near as dangerous as driving while drunk. Make Alcohol illegal, Legalize marijuana!

[Michael_Sexton]

reckless driving.careless driving.If you draw attention to yourself by how you drive there are ways to deal with it.

[BillG4500]

I don't see why people worry so much about having a "breathalyzer equivalent" test for marijuana. I worked for many years as a public defender and handled countless DWI cases, many of which were "DWI Drugs" cases rather than cases involving alcohol. There are many substances that cause impairment, but we only have a legal limit for alcohol. The test is not required for a DWI conviction with alcohol though. Often, people refuse to blow, or they'll be arrested at a time when the machine is down but are charged anyway. Sometimes evidence of the test is excluded because it wasn't calibrated right or the officer wasn't certified or something. With alcohol, there are really two laws, one that says you're guilty if you blow over the limit, and another that says you're guilty if you're impaired on alcohol while driving to the point that you are a danger on the road. Without the test showing someone is over the limit, the prosecutor will introduce evidence of intoxication and usually get a conviction. In fact, most people just plead as they would have done had they blown over the limit. If not, the officer will testify about what led him to believe the person was intoxicated, about the field sobriety tests, and so on. And now there's usually video as well which is pretty powerful evidence. Acquittals are rare.

I have seen DWI Drugs cases involving all sorts of drugs. They're handled the same as alcohol cases where there is no test. Usually, they're prescription drug cases, benzodiazapines like Xanax or narcotic pain meds or muscle relaxers, or a combination. Those drugs can really mess people up. Normally they'll have a drug test that doesn't show intoxication, but does show drugs were in the person's system, and they'll have field sobriety tests, video evidence and all that too. If it's marijuana or another illegal drug, it's the same, and most of the time people will plead guilty and take their punishment, and if they force a trial, most will be convicted.

That's just the way it works and it works fine. There is no pressing need to have special test for pot.

[avalon288]

Pot smokers like alcohol drinkers who use and drive care only for their own personal freedom. They don't care about you or your children in other cars. You are impeding their choices and they don't like it. You are an obstacle and its your fault. For these reasons, people under the influence need to be punished severely if they are caught.

[judderwocky]

except the two are nothing alike. idiots like you are fun to listen to though.

[dnamj]

No, it does not bring up any more questions about impaired driving. Seriously, time to stop with the scare tactics.

[danielle_mom]

I want to break the law and if I kill someone it is no my fault. People need to have common sense. If you are using a drug that could possible impair your judgement do not get behind a 2 ton highly mobile peice of steel.