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Police face new challenges when determining if someone is too high to drive

As states across the country legalize marijuana, efforts to determine whether someone is too high to drive is becoming a thorny public health issue. From brain functioning analyses and phone apps to training police officers on looking for signs, Hari Sreenivasan reports from Massachusetts, the latest state to start opening marijuana dispensaries, on efforts to resolve the dilemma.

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  • ADRIAN ALVAREZ:

    Is it nice and snug?

  • HARI SREENIVASAN:

    Yeah. This is very Amelia Earhart, old school.

    I'm being fitted with a functional near infrared spectroscopy device – or fnirs for short – at a lab at Massachusetts General hospital.

  • JODI GILMAN, ASSISTANT PROFESSOR, HARVARD MEDICAL SCHOOL:

    start from 100 and count backwards by seven.

  • HARI SREENIVASAN:

    Ninety three.

    Jodi Gilman is an assistant professor at Harvard Medical School and a researcher with the hospital's Center for Addiction Medicine.

  • HARI SREENIVASAN:

    79.

    As I count backwards, the nodes on my forehead detect the amount of oxygen in the blood, in my brain – an indication of how hard parts of my brain are working. Each node is shown on screen as colored squares.

  • HARI SREENIVASAN:

    23.

    It's harder than it looks because I caught a very early morning flight.

    Nine, two. Thank god it's over.

    But Gilman is not running a study on sleep deprivation, she's developing a way to determine when drivers are high on marijuana. She's demonstrating this brain imaging device on me while I'm drug-free but in her study she's looking at the brains of volunteers before and after taking a dose of synthetic cannabis.

  • HARI SREENIVASAN:

    How do you get from here, to whether or not someone is impaired behind the wheel?

  • JODI GILMAN:

    So the idea is that your brain looks different when you're intoxicated. What we're looking for is a neural signature of being high. So we're looking at the brain when you're not high and the brain when you're high and trying to detect differences between those two brain states.

  • HARI SREENIVASAN:

    Gilman's research is very relevant for Massachusetts.

    In November 2016, voters approved a recreational marijuana ballot initiative, joining seven other states in legalizing the drug. Brick and mortar dispensaries could open as soon as this summer.

    The coming influx of legal weed has many in the state concerned that it will mean more people are driving while high.

    If an officer pulled me over right now and suspected I was drunk, police could test for alcohol in my system. But with THC, the psychoactive ingredient in marijuana, it can be in my system for weeks, and figuring out whether I'm impaired because of it is really difficult.

    Gilman and her co-investigator, Dr. Eden evins, have tested about 50 subjects so far, and found that their test can at least tell the difference between the effects from THC versus a placebo.

  • DR. A. EDEN EVINS, DIRECTOR, MASS GENERAL HOSPITAL CENTER FOR ADDICTION MEDICINE:

    This just shows that we have sensitivity, that it passes the bar and we could go to the next step. We have to be able to distinguish small doses that don't cause intoxication or impairment from a dose that causes intoxication or impairment. So it's like being able to tell the difference between a .01 of alcohol on a breathalyzer and a .08.

  • HARI SREENIVASAN:

    The hope is that the test will eventually be able to spit out a number that quantifies the likelihood that a driver is impaired.

  • JODI GILMAN:

    The biggest advantage of something like this is that it would be objective. It wouldn't rely on somebody's subjective opinion. It wouldn't rely on what the person thought of you what the person's preconceived notions are. This would be a number.

  • POLICE OFFICER:

    Keep your eyes open for me.

  • HARI SREENIVASAN:

    But in the absence of new tools for detecting marijuana impairment, law enforcement are using some of the same methods as they do to detect impairment from alcohol. That means relying on the judgement of individual officers.

  • POLICE OFFICER:

    You see this with my finger?

  • HARI SREENIVASAN:

    On Cape Cod, these two dozen police gathered for two days of advanced training on spotting impaired drivers. The class refreshed their skills, including how to administer the standard field sobriety test and gave officers more information about drugs.

  • RICH TROY:

    Effects of cannabis – brief attention span.

  • HARI SREENIVASAN:

    Rich Troy is one of the instructors, he's a sergeant in nearby Dennis, Massachusetts and a former drug recognition expert. That's, a national credential developed in the 1970s to identify drug impaired drivers.

  • RICH TROY:

    Everybody's different. So just like drink some people can drink a lot of beer and some people have one beer and they're falling over giggling. The same holds true for drugs.

  • HARI SREENIVASAN:

    Law enforcement officials in the state say there has to be more emphasis on training, as access to marijuana dramatically increases in the state.

    John Carmichael is the police chief in Walpole, Massachusetts and a member of a state special commission studying the issue of operating under the influence, or OUI

  • JOHN CARMICHAEL, CHIEF OF POLICE, WALPOLE, MA:

    We've been dealing with the OUI marijuana issue just like we did before legalization. The problem is here in Massachusetts it's not very effective.

  • HARI SREENIVASAN:

    Under Massachusetts state law, there is no requirement that someone who is arrested submit to an officer evaluation. Carmichael would like to see the legislature change the law.

  • JOHN CARMICHAEL:

    Make it mandatory that if somebody is arrested on probable cause on a motor vehicle stop for OUI drugs and they're transported back to the police station, that they've given implied consent that they will take that test and if they refuse then they should lose their driver's license just as if they refused a breath test.

  • HARI SREENIVASAN:

    The state commission will be providing recommendations on law changes by the end of the year, but Carmichael wants to see more research on measuring impaired drivers .

  • JOHN CARMICHAEL:

    They have to come up with a good standard and something that's backed by the science. You know, I just don't think we're there yet.

  • HARI SREENIVASAN:

    While researchers and lawmakers try to figure out how to measure the level of impairment, the industry is ready to go. Here at Cannacon Massachusetts there are booths for everything from seeds to certified public accountants.

    And at this industry convention, marijuana impaired driving is not perceived as a big problem.

    Deneb Dollinger runs a company that puts on cannabis related events in Massachusetts.

  • HARI SREENIVASAN:

    Is there a problem with people driving impaired?

  • DENEB DOLLINGER:

    Honestly, I don't think there is a problem with it.

  • HARI SREENIVASAN:

    Darren Jalbert works with a cannabis seed producer.

  • DARREN JALBERT:

    There is no epidemic of impaired driving, high driving. It's a push to recriminalize or re-prohibit cannabis culture and activity and consumption.

  • HARI SREENIVASAN:

    Chip Lennemann works with a company that makes plant nutrients.

  • CHIP LENNEMANN:

    I think there's a lot of people out there driving around high, or smoking while they drive. Do I personally feel that it's the same as someone driving around drunk? No. I feel people have more control when they're stoned or high than when they're drunk.

  • MARILYN HUESTIS, SENIOR FELLOW, THE LAMBERT CENTER FOR THE STUDY OF MEDICINAL CANNABIS AND HEMP, THOMAS JEFFERSON UNIVERSITY:

    They have no understanding of the fact that cannabis can be so impairing.

  • HARI SREENIVASAN:

    Marilyn Huestis is a researcher who studies the effects of cannabis at Thomas Jefferson University in Philadelphia.

    Huestis used a driving simulator, giving participants a dose of THC and testing their driving skills. She says cannabis affects motor control and the ability to make decisions.

  • MARILYN HUESTIS:

    They may be able to drive home from work. But for instance the person who slams on the brakes in front of them or someone comes out of the roadside on a bicycle into their lane, all of those things are affected by cannabis and their ability to respond accurately and correctly.

  • HARI SREENIVASAN:

    Because it's so difficult to confirm that marijuana is the cause of any one crash, data on traffic crashes and marijuana varies.

    But in studies looking at research from all over the world, the risk of crashes doubles when the driver is under the influence of marijuana.

    Huestis believes there is risk to public safety and says impairment can be detected by trained cops.

  • MARILYN HUESTIS:

    The best thing is to first have a documentation of the impairment by the officer and then once you have the impairment, now you need a biological sample that will tell you which are the drugs that may be contributing to that impairment.

  • HARI SREENIVASAN:

    There are devices used at roadside stops that test saliva for the presence of THC, and other drugs. They provide results in a few minutes with a quick mouth swab, but only show the presence of THC, not necessarily impairment.

    A California company called Hound Labs is developing a marijuana breathalyzer that detects whether a user smoked or consumed cannabis in the past few hours. But it's still being tested and is not yet available.

  • MATT ALLEN, FIELD DIRECTOR, ACLU OF MASSACHUSETTS:

    We can't base policy on innovations that are yet to happen.

  • HARI SREENIVASAN:

    Matt Allen is the Field Director for the ACLU of Massachusetts and also serves on the state commission looking at driving while high.

  • MATT ALLEN:

    I think that it's understandable that law enforcement agencies are seeking the silver bullet that's similar to a breathalyzer because it establishes beyond a reasonable doubt proof of impairment in court. So it's expedient. At the same time at the ACLU we can't let expediency in court trump science, evidence, and civil liberties.

  • HARI SREENIVASAN:

    Allen is concerned that some in Massachusetts might want to institute a hard limit on the amount of THC in drivers. Since THC can linger in the body for weeks, it's not a reliable proxy for whether a driver is impaired.

  • MATT ALLEN:

    We want to make sure that any recommendations that come out of the operating on the influence commission really are based in science and not this idea that impairment can be established by blood tests.

  • JODI GILMAN:

    So what did that feel?

  • HARI SREENIVASAN:

    Alright!

    Back at Massachusetts General Jodi Gilman and Dr. Eden Evins are expanding their research. Last month, they received a 1.5 million dollar grant from the National Institute on Drug Abuse.

  • HARI SREENIVASAN:

    So someday in the future you could get pulled over and the state trooper walks over, has you put this baseball cap on. They don't need to be able to interpret scans, right?

  • JODI GILMAN:

    No. No not at all. So the idea would be to make this dummy proof to make this as easy to use as possible so it doesn't require any specialized training.

  • HARI SREENIVASAN:

    They hope to have a prototype of their brain imaging device being tested on the roads by next spring.

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