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Drugged Driving THC Fact Page – DUI Lawyer


Grand Rapids Criminal Defense Lawyer


Medical Marijuana, THC and Drugged Driving.


As more states enact medical marijuana laws (25 medical marijuana states plus D.C. at last count), the new marijuana laws directly conflict with long-enshrined, strict Zero Tolerance prohibitions on driving under the influence of any Schedule 1 drug, which includes cannabis, more commonly also known as marijuana.


It is important to note that ALL STATES prohibit driving a motor vehicle while you are impaired. If you are impaired by any substance, you are not allowed to drive, whether you are impaired by prescription drugs, alcohol, cocaine, marijuana, water, vitamins, etcetera. The important difference between drunk driving and drugged driving, is that with alcohol there is a clearly defined, federally mandated .08 blood alcohol (BAC) limit. Contrary to public perception, it is not illegal to drink and drive, so long as your ability to operate the car safely is not impaired OR you are not over the legal limit of .08.


In cases involving low alcohol readings under .08 or someone who is allegedly impaired by prescription drugs, the prosecuting attorney must prove actual impairment of the driver beyond a reasonable doubt. Impairment can be shown by evidence the driver was weaving, driving over the fog line, erratic driving, failure to use headlights, speeding, and failure on the roadside sobriety tests. Assuming you are not over the .08 limit or are impaired by prescription drugs, a jury would deliberate and have to decide whether the state or local prosecutor had proved impairment beyond a reasonable doubt.


Despite numerous laws that allow medical marijuana, all 50 states and the federal government continue to classify marijuana as a Schedule 1 controlled substance, meaning that:  (a) it has a high potential for abuse; (b) has no accepted medical use; and (3) there is no accepted safety standards for using the substance – even under medical supervision. No doctor prescriptions may be written for a Schedule 1 substance.  


All fifty states have some form of Zero Tolerance laws. Zero tolerance laws give the same drunk driving type penalties to those who operate a motor vehicle with any amount of a Schedule 1 drug or illegal substance in their bodies. Unfortunately, the states that have passed recreational marijuana laws or medical marijuana laws have not been as fast to change or modify their Draconian zero tolerance laws. This leads to absurd results, where a patient is state-authorized to use medical cannabis but unable to drive wiith active THC (a schedule 1 drug) in their bloodstream or the marijuana metabolite 11-Carboxy-THC.

It is unlikely anyone would seriously posit that someone with THC should be treated the same as someone stone cold drunk, high on heroin, LSD, or ecstasy.


And yet, this is the present reality in many states.


Driving Under the Influence of THC – Zero Tolerance in Michigan.


After the Michigan Medical Marihuana Act was voted into law November 2008, it was unknown whether Michigan medical marijuana patients driving abilities would be protected by the Michigan Medical Marihuana Act. It was thought that medical marijuana patients should be allowed to use marijuana and drive, in the same manner that they could had they just ingested Vicodin or some other type of prescription drug, so long as the marijuana did not materially affect their ability to safely operate a vehicle.


In May 2013, the Michigan Supreme Court issued a unanimous 7-0 decision, People v Koon, where it overruled a lower court and decided that the Michigan Medical Marijuana Act superseded the state's Zero Tolerance law. What this means, is if you are a registered medical marijuana patient (or a Section 8 patient) and have active THC in your body, the presence of the active THC cannot be used to automatically convict you. Prosecutors cannot simply convict you under the Zero Tolerance law by producing a blood test result showing you had active THC in your bloodstream. Instead, a prosecutor has a much higher and harder burden of proving, beyond a reasonable doubt, that your driving ability was actually impaired by the active THC in your body. In other words, the government must show your ability to operate a car was actually impaired by the active THC (e.g., weaving, excessive speed, erratic driving, etc), just as they would for any other prescription drug. 


Medical Marijuana States.


A few medical marijuana states have taken action to correct this perceived unfairness. On the date of writing, Colorado had introduced a 5 ng/ml blood standard that a jury can use to "reasonably infer" that the driver was impaired by THC. Both Nevada and Ohio have per se impaired limits of 2 ng/ml of blood; Montana has a per se limit of 5 ng/ml; and Pennsylvania had a 1 ng/ml THC "guideline," meaning a THC blood level can be introduced as evidence of impairment, but is not an automatic limit. In contrast, Washington State instituted a 5 ng/ml of blood per se limit. PLEASE NOTE: marijuana and driving laws are changing rapidly. To keep this page current on all 50 states on a daily basis is beyond its scope. These amounts were accurate when this page was written, but do NOT rely on them; seek out the law in the state where you intend to drive and educate yourself. 


Unlike alcohol, there are simply not not enough studies or indicators that lead to setting a specific per se intoxication/impairment limit for THC. The effects of alcohol are rather predictable, and the studies on alcohol and driving are innumerable. Marijuana and its effects on drivers is much more subjective, and individualized. The studies that exist, tend to show that users of marijuana act the opposite of drunk drivers. Drivers with marijuana in their bodies tend to slow their driving, allow more distance between cars, and drive more like one of your grandparents would. Unlike alcohol which is a stimulant and has been shown to limit a drinkers inhibitions and make them feel they are superman (or superwoman) and thus impervious to harm, marijuana tends to act more like a sedative and its users become more cautious and careful.  


However, the vast majority of medical marijuana states still have zero tolerance laws on the books, and in these states, driving a motor vehicle with any amount of active-THC in the bloodstream can lead to a drugged driving conviction, just as if you were driving over the legal limit of .08.


There seems to be a lot of legislative will to set arbitrary THC standards. This may be in part, because marijuana is highly controversial and because there are few scientific studies that are considered unbiased. There is simply no studies that demonstrate with any reasonable certainty the amount of THC which causes impairment of a driver's ability. For example, the authors of legislation that sets a .05 ng/ml limit will readily admit that this amount is not based on any scientific study or data.  


The states that permit recreational dn medical marijuana will eventually implement some type of THC standard, as the zero tolerance laws left over from decades ago should not longer be applied.


How Long after I Smoke Marijuana Will Active THC be in my Body?


There is no easy answer. There is some scientific support that shows that smoking cannabis acutely impairs driving abilities for the first hour. Active THC levels begin drop over the next two hours, followed by a residual period which lasts 2-3 or more hours. If marijuana is orally ingested, THC levels peak 2-3 hours later.


Assuming that the cannabis ingested is not a high THC strain, THC levels should drop below 5 ng/ml about 4-6 hours after smoking.


Active THC vs 11-Carboxy-THC.


The Michigan Supreme Court (People v Feezel, 2010) ruled that the marihuana metabolite "11-carboxy-THC" (the substance that stays in your body for up to three weeks) was a ‘derivative’ of marijuana  As a derivative, 11-carboxy-THC was/is not a Schedule 1 controlled substance. Thus, a person who only has the metabolite cannot be prosecuted for zero tolerance drugged driving. Although it is illegal to drive with active THC, it is not illegal to drive with the 11-carboxy-THC metabolite.