cannabis and driving
cannabis and driving

You can have a beer and drive, but what about driving after a joint?

Why Blood? 

You can drink a beer without blowing over the limit, but how about a puff on a joint without enriching your blood with THC above Canadian per se law? 

As I discussed, saliva testing for cannabis has been left on the curb because of an official research group’s incompetent suggestions. The Canadian Society of Forensic Sciences gathered two singular reports (1,2) which Justice Canada used to write Canadian drug driving laws. This included cannabis and alcohol. You would think the roadside detection method chosen by the RCMP would be a reliable one, right? Given the awful mess cannabis legalization has left, you should not be surprised to find out otherwise.  

Blood per se limits (1) have been written by that same research group, and the RCMP have decided that is the only thing they need. For this method, claims of false negatives were a bigger concern. In response to this, a blood THC limit just narrowly above zero tolerance has been given to a country with legal cannabis. While contradicting themselves by not setting an oral fluid limit (3) at levels low enough to be an effective, reliable means of initial detection for fear of false positives.  

A failed decision, which has now left everything solely up to the false positive ridden blood analyzing. This backwards way of thinking is no laughing matter considering this is the new way of Canadian roadside enforcement. 

If Einstein said, “Science without religion is lame, Religion without science is blind” (4), I am sure he would call law without science no more visionary.  

Per se Law is a science-based limit of drugs within the body which should be set at a level that is known to cause impairment. 

Canadian law chooses to avoid directly citing any research that declares 5 ng/ml in blood as being capable of dictating impairment (5-8.) Missing a thorough study (9) suggesting a more acute THC concentration relative an illegal alcohol limit. Rather than using proper analytical evaluation to set per se law, Canada instead took vague considerations from countries without legal cannabis (1, 10-12,) or a now outdated study of studies (13.) 

Regardless, a lack of actual simulated drive data, any attempt at dictating impairment through a blood THC limit becomes void. Real world scenario lacks an ability to evaluate many different variables that are controlled for in a study, such as last time of use (14, 15.)  

Scientific suggestions and set limits are also designed for those without tolerance (1, 6, 7, 9, 15-23.) As unfair as that is, there is no practical way to adjust for this. What becomes drastically unconstitutional, is making arrests based on a legal substances toxicological presence without actually proving impairment (1,9.)  

Considering some research that was left out deems a single 3.95% THC “cigarette” as being capable of producing a body sway equivalent to 0.05% BAC (6,) viable data is clearly too thin. Upon hearing such rash claims, even a novice cannabis user would turn an ear to a more practical story. Perhaps an undisclosed addition of tobacco combined with cannabis created unknown potentiated effects. This did occur in another consistently cited studies design (8) – without adjusting their conclusion accordingly. 

Another hand of data suggesting 5 ng of THC per ml blood as a limit of impairment is from forensic Motor Vehicle Accident and roadside inspection data (4.) Representing a battery of toxicological research detecting THC at this quantity in blood samples taken from impaired drivers or those responsible for crash during inspection, rather earlier vehicle operation. After a 1-4 hour delay in between drive and collection time, there will be a major loss of THC from the blood. (14, 15.) The forensic data suggests this postponed test accurately calculates a more acute amount, only probably, present during the earlier traffic violation. In reality, a dense array of cases at low THC blood concentrations simply showcases cannabis’ overall popularity, as opposed to its direct implication of crash risk between 1-5 ng/ml.  

Penalties for drug-impaired driving.

This is due to THC’s habit of loitering around in your fat well beyond that wonderful sense of inhibition. A mass populous of patients and users have a baseline THC level in that range, unrelated to impairment. Giving misconstrued cause to any conclusions which are drawn. Blood is not a clear window into someone’s cannabis use history. You cannot look back in time to measure a person’s cognitive function through this median (1, 14, 15.) Impairment entirely depends on how much THC is in your brain actively agonizing cannabinoid receptors. A systematic conversion to evaluate that quantity from levels found in your blood is absent from existence. Yet to fight a tragedy only ever so slightly related to Cannabis, toxicology over reason seems to be pushing in. Alternatives are vague, beyond an appropriate oral fluid cut-off, no human-based decision or standardized test can truly depict recent cannabis intoxication (1, 2, 20.) The fact is, any amount of cannabis smoke will now make driving illegal, for a potentially unknown lengthy period of time. 

More False Positives than Negatives 

In occasional smokers enjoying a couple joints throughout the week, for example, this false negative possibility is certainly not the case. Chances are high that you have an illegal baseline blood THC limit dripping from your fatty tissues until after you have completely quit for two days, possibly up to a week. (14-17, 24-30.) 

Daily users smoking a joint or two a day – five times a week, for at least six months, will need to quit for a month to be able to drive legally again. 

This time is dependent on several facets including your natural metabolic rhythm, daily routine, intricate biological structure, duration of lifelong cannabis use, and even gender. (15, 16,)  

Contrary to popular belief, actual BMI does not directly correlate with cannabis’ longevity in testing. (27.) Controversy females, who show longer detection times than males, have more adipose tissues for cannabinoids to soak into. Exercise and stress can help flush out the cannabinoids faster (31, 32;) although, this also may also raise your blood concentration slightly. In other words, don’t panic before the test. Unless you even had a single puff in the past few hours then this won’t matter, you will be already above an illegal limit. 

How much can you smoke before driveing?  

The Per se Limit is supposedly “science-based, ” in reality it is “limited-science-available.” You cannot smoke weed and drive! 

In fact, an inexperienced smoker only needs 0.1-0.5 MG of cannabis at 20% THC to bring their blood to an illegal limit. Shockingly, this is only 2-10 mg of CBD dominant cannabis at only 1% THC!  

Luckily this will only be present during peak concentration before a rapid 95% decline occurs(15,) a period of time too short to catch in a sample. Smoking a tiny 0.01 grams (10 mg) puff off of the bud will potentially cause detectable unlawful driving. This is equal to about 20 mg of CBD dominant bud. Those with tolerance may actually need to smoke less for their baseline levels to boost an extra 2ng/ml (17,) while also needing more for any significant physiological alteration to occur. Is this enough to even get a newcomer stoned? 

Chalkboards or Lounge Napkins Ready? Let us begin…

2 MG of THC is an average threshold dose for smoking, comparing to a more familiar 10 mg edible dose. (33, 34.) Threshold means the lowest possible dose which will produce any effect. Smoking 2 mg should be fairly sufficient for someone with absolutely zero tolerance. Despite a broad person to person variance, dependent upon many catalysts. Whereas a seasoned smoker will need much more – exactly like a marijuana patient trying to take that single 10 mg edible dose. 

Smoked cannabis is anywhere from 10-45% bioavailable. (33.) This depends on smoking technique, biological adaptation developed from years of smoking history (15.) The presence of entourage cannabinoids and terpenes like myrcene and limonene (35, 36,) or even adulterants like the added tobacco (8, 37) will also greatly impact potency. For bud at 20% THC, you need 0.01 grams to achieve a 2 mg smoked dose, with only 0.2 – 1 mg actively absorbed into your whole body.  

You have 5 litres of blood (38,) 5000 times 1 ml. So if you divide total THC (0.2-0.9mg) by total single 1 ml units in your body (5000,) and then multiply by 1 million to convert mg to ng, you end up with 40-180 ng/ml.  

You can call my math crude, I want to agree. I’ll even confess some disbelief in its viability while admitting surprise seeing the answer. Given some extra loss during metabolism, the lower end actually matches data seen in deeply thorough studies (33, 39.) Done by pumping blood from people while they smoked weed.  

Keep in my mind, doubling the dose will not double the blood concentration. THC absorption and disposition travelling between watery blood and fatty tissues is not so streamlined. Hence why smoking a 100 mg dose will not bring your blood concentration anywhere near 2000-9000 ng/ml. You will be closer to 200-400 ng/ml according to rigorous testing. Blood concentrations will deplete to 95% of this volume approximately one hour after smoking time (1, 14-17, 20, 27.) Giving you 2 to 9 ng\ml in your blood an hour after smoking 2 mg of THC. Whereas a drastically increased dose will only represent a slight change in a blood test by the time the sample is extracted. This will decrease to approximately 10-40 ng\mg an hour after a 100 mg dose, or one half gram of 20% THC bud. 

There is always the chance the amount left in your blood after this hour relates more with how much protein is present within your individual matrix (16, 38) – opposed to what the original smoked dose was. Protein makes up 5% of your blood and attracts THC, far less effectively than fat (33.) Overall maximal absorption is more acute in females (20) bringing a gender diversity issue to blood per se laws. Especially since males experience more acute loss of visuomotor function. (23.)  

Fake Zero Tolerance 

Even the Department of Justice states on its website that 2ng/ml in blood only declares use of cannabis in the unknown past (40.) A summary offence is still given for that insignificant amount. (Fig 1.) A faux lenience sitting only slightly above the lowest possible detection limit, 1ng/ml, used in places less legal to possess THC at all (10-13, 20).  

Cannabinoids rapidly enter your brain while soaking into other fatty tissues. During this time, THC is cleared from bodily fluids almost as quickly. For brand new smokers there is a small chance your blood may be vacant of THC by the time you are arrested, taken to the station and tested. This presents a possibility stoned drivers can go undetected even through a Drug Recognition Experts (DRE) evaluation. This is used by Justice Canada as an excuse to enact this 2ng/ml “public safety” policy (40.) Deliberately setting limits below what scientifically classifies as impairment. While also allowing any police officer to perform a blood extraction based upon suspicion of impairment, bypassing a DRE.  

Choosing more strict action means more impaired drivers are caught, while also meaning more wrongful convictions will take place. This was Justice Canada’s choice in “the least objectionable option” as the official report (1) by the CFCS\DDC stated. While ignoring their other reports on saliva testing demanding more than one tool be used in roadside detection. Actually giving the RCMP full decision in the tactics employed. A second reliant analytical tool cannot be an officers determination of any one single factor used to validate your arrest; such as a failed Standard Field Sobriety Test, having red eyes, slow speech, tremors, an odour of cannabis etc.   

A ‘just in case’ per se limit – easy enough to be called a drug policy rather motor vehicle safety. This false negative concern is potentially valid for users with no cannabis experience, so long as a definite understanding of cannabis induced cognitive deficit continues to be blatantly ignored.   

Illegally High By Association 

If it still seems impossible a spec of a crum could do anything; consider this, both per se and oral reports from the CSFS\DDC (1, 2,) warn of passive exposure. It is literally illegal to sit in a friend’s smoke session without partaking, and later drive. You probably smell of weed after, too. The oral report stated that 25ng/ml cutoff will make false arrests from passive cannabis exposure impossible! (2) Oops, no Draeger – more false arrests. Your blood limit may be above 2 and even 5 ng/ml after one of these sit-ins (41-44.) Further, official reports reference studies which used Dutch coffee shops filled with weed much less potent than Canadian cannabis. Not a realistic look at actual outcomes. 

This brings in another use for THCCOOH testing at amounts greater than 10ng/ml. (24, 45.) This inactive breakdown product of THC will not be detected at these more acute concentrations in oral fluid after passive exposure, only in recent direct use. This negates false positives. While a limit of detection quantity of active THC in oral fluids can prevent any possibility of false negatives. 

An Analyzed Truth To Be Continued 

Justice Canada is the one writing the thin excuses for why these zero tolerance limits are used and why driving during abstinence from chronic cannabis use should be unlawful. Patchy laws which will continue to be exploited throughout this series.


Featured image courtesy of Puff Puff Post.


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