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Bruce Alan Block, PLC

Represents clients in Grand Rapids, Michigan, and West Michigan communities of Ada, East Grand Rapids, Kentwood, Cascade, Wyoming, Byron Center, Lowell, Caledonia, Cascade, Rockford, Holland, Grand Haven, Grandville, Kent County, Ottawa County, Muskegon County, Barry County, Ionia County, Newaygo, Montcalm, and Allegan County.
We represent students from Calvin College, Aquinas College, Grand Valley State, Cornerstone University, Grand Rapids Community College, and Michigan State University.

Bruce Alan Block, PLC
Attorney and Counselor at Law
Phone: (616) 676-8770

1155 East Paris Ave. SE, Suite 300

Grand Rapids, MI 49546

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Drugged Driving THC Fact Page – DUID Lawyer

 Grand Rapids Criminal Defense Lawyer


See our new page Michigan Roadside Saliva Drug Testing and DRE Experts


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 then drive, so long as your ability to operate the car safely is not impaired AND you are not over the presumed drunk 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 with 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.


Drug Recognition Expert (DRE).


As more states legalize the possession and use of marijuana for medical and recreational purposes, the police are starting to take a closer look at persons who are driving while impaired by marihuana. This is somewhat virgin territory. The police always used to focus on alcohol, the beverage of choice for most drunk drivers. However, the number of drunk drivers is decreasing every year. The new focus of the police is on drug impaired drivers. The penalties for driving impaired by marihuana or any substance is the same as alcohol. Police are being sent to special classes so that they can detect when a driver is under the influence of marihuana or some other drug. After about a week of classes, these police officers are then deemed to be "experts." This is not a joke, and if you run into a case where you are accused by a police officer who is supposedly a so-called "Drug Recognition Expert" you should seek legal counsel immediately, especially someone who has dealt with DRE officer cases before.    


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 materially 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. 


No Reliable Test or Studies as to THC Impairment Levels.


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 carefully. 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 alcohol legal limit of .08. We are aware of a case in Grand Traverse County, Michigan where a recreational marijuana user (not a medical patient) was charged with a 15 year serious felony for operating a vehicle with marijuana in her body causing death. Her active THC level was 1 ng/ml. 


Arbitrary THC Levels.


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. To date there are simply no studies that demonstrate with any reasonable certainty the amount of THC which causes impairment. The legislators that passed laws setting a .05 ng/ml limit would no doubt readily admit that this amount is not based on any scientific study or data.  


The states that permit recreational dn medical marijuana will have to 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 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 in Michigan. But be aware, we have heard that driving with the marijuana metabolite is still illegal in many states. 




Contact Us


Attorney Bruce Alan Block is a Grand Rapids, Michigan criminal defense lawyer who has successfully handled drugged driving, OUID, OWI, drunk driving, drugged driving, impaired driving, driving while impaired, driving while visibly impaired, and more. He also helps those whose license has been suspended to reinstate their driver's license. Put his years of experience to work for you.


If you or a family member has been charged with or accused of a marijuana driving crime you need immediate advice from an experienced criminal defense attorney. Contact our Grand Rapids, Michigan, criminal defense lawyer at (616) 676-8770.




Bruce Alan Block, PLC

Attorney and Counselor at Law
1155 East Paris Ave SE, Suite 300 Grand Rapids, MI 49546
Phone: (616) 676-8770


Serving Clients throughout Western Michigan, in Grand Rapids, Ada, East Grand Rapids, Kentwood, Cascade, Wyoming, Byron Center, Wyoming, Caledonia, Cascade, Rockford, Holland, Grand Haven, Grandville, Kent, Barry, Ottawa, Muskegon and Ionia County. We represent college students from Calvin College, Aquinas, Grand Valley State University, Cornerstone University, Grand Rapids Community College, Michigan State University, and Western Michigan University.


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