These DUI Laws Are an Irrational Hangover From Pot Prohibition

States should stop treating sober cannabis consumers as public menaces.


Four years ago, Pennsylvania allowed patients suffering from any of 17 serious medical conditions to relieve their symptoms with marijuana. But there was a catch: If they used cannabis as a medicine, they could no longer legally drive.

Last week the Pennsylvania House of Representatives approved a bill that would eliminate that legal disability by requiring evidence of impairment to convict medical marijuana patients of driving under the influence (DUI). That reform points the way to a long overdue reevaluation of DUI laws that irrationally and unfairly punish cannabis consumers who pose no threat to public safety.

Thirty-three states have legalized medical marijuana, and 11 have taken the further step of allowing recreational use. The list is likely to grow next week, when voters in five states will consider marijuana initiatives.

Even as pot prohibition continues to crumble across the country, many states are still treating sober cannabis consumers as if they were intoxicated. Under Pennsylvania's current rule, any driver with a tiny amount of THC or an inactive metabolite in his blood (one nanogram per milliliter) is automatically guilty of DUI.

Eleven states are even stricter than Pennsylvania, making it illegal to drive with any amount of THC or its metabolites in your blood. Because those chemicals can be detected long after marijuana's psychoactive effects have worn off, that "zero tolerance" policy is akin to prohibiting all drinkers from driving, even when they are sober.

Half a dozen states, including Pennsylvania, have "per se" laws that define DUI based on the concentration of THC in a driver's blood, while one (Colorado) allows an inference of guilt when that level reaches five nanograms per milliliter. But these laws don't make sense either.

Because THC, unlike alcohol, is fat-soluble rather than water-soluble, there is no clear or consistent relationship between THC in the blood and THC in the brain, which means THC blood levels do not correspond neatly to degrees of impairment. Complicating the situation further, individual responses to a given dose of THC vary widely, especially when you compare occasional marijuana users to regular consumers, who may develop tolerance to the drug's effects or learn to compensate for them.

2016 study sponsored by the AAA Foundation for Traffic Safety concluded that "a quantitative threshold for per se laws" based on THC blood levels "cannot be scientifically supported." That's because, as the National Highway Traffic Safety Administration explained in a 2017 report to Congress, the concentration of THC in a driver's blood "does not appear to be an accurate and reliable predictor of impairment."

The Congressional Research Service concurred in a 2019 report. "Using a measure of THC as evidence of a driver's impairment is not supported by scientific evidence," it said.

Thirty-two states recognize that THC in a driver's blood is not enough to prove impairment. They require additional evidence, such as erratic driving or physical and behavioral signs of intoxication.

The Pennsylvania bill would adopt that standard for medical marijuana patients, although it really should be extended to all cannabis consumers, since the validity of a per se rule does not depend on an individual's reasons for using the drug. The marijuana legalization initiative on Arizona's 2020 ballot takes the latter approach, replacing that state's current zero tolerance standard, which already makes an exception for medical use.

Even states that have legalized marijuana for all adults 21 or older do not necessarily have rational DUI laws. Illinois, Nevada, and Washington make drivers automatically guilty at THC blood levels that regular consumers commonly exceed even when they are not impaired, while Michigan still has a zero tolerance law that treats any amount of THC as conclusive DUI evidence.

Although zero tolerance and per se laws were presented as traffic safety measures, they are really just another way of punishing people for defying the ban on marijuana. When that ban is lifted, such laws are an indefensible hangover from an unjust prohibitionist regime that was rightly abandoned.

© Copyright 2020 by Creators Syndicate Inc.

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  1. If only there were a LUI crime for legislators, and they had to obey all the laws they inflict on the serfs, such as taking random drugs tests and going to jail if they flunk.

    Speaking of which gives me an idea. Wouldn’t it be grand if legislators could be sued for malpractice, which would include lying about their legislation, as when they claim renewables will save the planet and be cheaper to boot, or that banning assault weapons will reduce handgun crime? And their malpractice insurance came out of their own pockets?

    1. Given that over half of congress critters are millionaires, I don’t think they are too concerned. Also find a DA or US attorney willing to take that case.

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  3. Realistically, how many people get stopped and tested for this without some sort of erratic driving?

    1. There are so many traffic laws, a cop can justify a stop against literally any car on the road. Once you’re stopped, the cop just has to find a pretext to demand a test. Tests aren’t performed just for stops for people who are driving erratically.

      1. Never agree to searches without warrants and never take field sobriety tests.they are traps. Just like speaking with law enforcement.

        You cant talk your way out of a DUI arrest. Never give the state evidence against you.

        1. The problem is that most states make it easy for a cop to claim probable cause and search your car without a warrant anyway (“I thought I smelled marijuana”)

          1. Even with “probable cause”, such as smelling weed, cops still need a warrant to search your vehicle.

            They ask to let them search because they either cannot actually get a search warrant or its too much hassle.

            DONT EVER give them permission, so you become a person that never gives permission to search no matter what police say.

          2. Just tell them it was hemp, not marijuana. Low THC hemp flowers are effectively legal now. So smells like pot shouldn’t be probable cause anymore (don’t know if this has been tested in court).

        2. “You cant talk your way out of a DUI arrest.”

          You can, but not by agreeing to the roadside circus. A flat denial of any drinking that day/night, works, if you can pull it off. “I seent it!”

    2. As far as I know it doesn’t happen a ton. Less than alcohol checks. But still, if they want to get you, it gives them one more way to do it.

    3. I got stopped last night on the way home because my license plate light was out. I had to do the eye test and I passed. The cop was nice, polite and professional.

      I kind of find it funny that this is now an issue because of cannabis. The government and police have been abusing the rights of drivers for years over alcohol, but, now that it’s weed it is starting to get some attention.

      1. ” I had to do the eye test and I passed. The cop was nice, polite and professional.”

        Was the cop also an optometrist and concerned you were physically unable to see your plate light was out?
        See above about not submitting to tests. See the dictionary as to the meaning of “nice.”

  4. Oh God, are we doing this?

    Drugs laws are unconstitutional unless, like the Prohibitionists, you amend the constitution to ban products like alcohol or weed.

    Public roads are regulated and mentioned in the constitution. If you use those roads, you can be regulated to not be unsafe to drive. Hence DUI laws.

    You cant get a DUI on PRIVATE roads.

    1. I own some parking lots and hold drag races occasionally.

      Cops hate it but they lost in court too many times so they avoid the events now.

      1. But did the cops lose on the track?

    2. Check your state laws, some do prohibit driving while intoxicated even on private property

    3. Yes, they can make laws like this. Doesn’t mean they should, or that the laws they do make are reasonable.

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  7. I think a lot of users in most places with medical marijuana laws are not registering because it puts you on all kinds of warning lists. Still just as easy to get it and generally cheaper on the black market.

    Just end the war on drugs.

  8. >>Under Pennsylvania’s current rule, any driver with a tiny amount of THC or an inactive metabolite in his blood (one nanogram per milliliter) is automatically guilty of DUI.

    should I turn myself in on retroactive charges?

    1. If PA bans fracking, they’ll need the money, so…sure? Though I thought you were in the Metroplex?

      How do the police plan on getting a blood sample at roadside to prove per se THC intoxication? Arrest em all and let the jail sort em out?

      1. I figure most days since the late 80s I’d qualify for “with a tiny amount …” and I’ve been through Pennsylvania plenty

    2. “should I turn myself in on retroactive charges?”

      Only if the statute of limitations has not passed.

  9. Big Pharma lobbyists and elected officials have protected people who have trace (and even unsafe) levels of Big Pharma drugs from being charged with DUI.

    Meanwhile, for decades those same Big Pharma lobbyists have opposed legislation to decriminalize cannabis and hallucinogens, claiming their legalization will increase auto injuries and many other horrors.

  10. PA’s medical marijuana law also prohibits people (who are allowed to buy/use medical cannabis) from owning guns.

    1. No law is valid if it requires me to waive any fundamentally protected right in order to exercise any other right or alleged privilege.

  11. And give up all those juicy fines?

    Oh, the humanity!

  12. Fer sures, dude. Everybody must get high. Now zap me another burrito.

  13. “Because THC, unlike alcohol, is fat-soluble rather than water-soluble, there is no clear or consistent relationship between THC in the blood and THC in the brain, which means THC blood levels do not correspond neatly to degrees of impairment.”

    kind of disappointing to read, as it implies that current alcohol DUI law is based on science that establishes a “neat correspondence” to degree of impairment. which it doesn’t. we need better research and methods for both, and NOT a presumption of guilt based on a number.

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