Marijuana is the conventional term. Cannabis sativa is the plant it is derived from. Its drug class is Cannabinoid. It is most commonly smoked, but can be orally ingested. THC, or tetrahydrocannabinol, is the main ingredient. This is the chemical responsible for marijuana’s mind altering effects. Common knowledge, right? What marijuana does to the brain and how “getting high” causes impairment is not so basic. And how its use affects functionality, especially as it relates to something like driving, is anything but elementary.
The potency of marijuana is related to the amount of THC it contains. According to the National Institute on Drug Abuse (NIDA) and other national studies, the THC concentration and strength of marijuana has steadily increased over the last few decades. Expressed as %THC, the higher the percentage, the quicker the absorption and “high” effect is felt.
When marijuana is smoked, it takes mere minutes to get from the lungs, to the bloodstream, and to the brain. As soon as the THC enters the bloodstream, it binds to receptors on nerve cells in the brain. This cell stimulation and the activation of these receptors releases dopamine, creating a feeling of euphoria, meanwhile simultaneously interfering with the function of certain areas of the brain associated with thinking, memory, pleasure, time perception, and coordination. While the effects of smoking marijuana may only last a number of hours, the presence of THC in the blood can remain for days to weeks after use.
Sans effect on the brain or body, factors such as potency, ingestion method, and frequency can equate to long-term levels in the bloodstream, indicating use. However, the presence of THC in an inpidual’s blood does not necessarily indicate whether the drug was used moments or days prior, as metabolites from marijuana usage remain in the blood for some time after the effects of “getting high” have worn off. Although blood tests can detect presence of active THC, unlike proving driving under the influence as it relates to alcohol, it is more difficult to prove marijuana impairment and if a driver is actually under the influence at the time of an accident or arrest, and therefore not capable of operating a motor vehicle safely. With drugged driving emerging as a national epidemic, federal funds granting specialized drug-impaired driver detection training, crime lab drug-testing equipment, and dedicated sobriety checkpoints have been implemented. Nonetheless, a bigger debate seems to surround how high is too high, as it relates to what blood level of THC impairs driving.
Experts nationwide sway on whether this correlation is legit and what realistically constitutes impairment. According to the National Highway Traffic Administration, “It is difficult to establish a relationship between a person's THC blood or plasma concentration and performance impairing effects ... It is inadvisable to try and predict effects based on blood THC concentrations alone.” Nevertheless, states such as Colorado and Washington have standardized a legal limit of nanograms of THC per milliliter blood as under the influence, much like the .08 blood alcohol concentration (BAC), as it relates to alcohol. Other states, such as Nevada and Ohio, have set a guideline, rather than a specific limitation. Michigan and Wisconsin legislation has decreed that marijuana is treated the same way as any other prescription drug and prosecutors must prove that a defendant was in fact impaired. In Arizona, Delaware, Georgia, Illinois, Indiana, Iowa, Montana, Oklahoma, Rhode Island and Utah, “zero tolerance” applies and per se legislation has been put into place, making it illegal to drive a vehicle with any detectable trace quantities of THC in one’s system. With these newly enacted limits and marijuana DUI laws as a whole, the question arises whether people who are totally sober, yet have THC in their systems, are wrongly arrested. Where does California stand in this debacle?
The state of California, amid others, has no per se limit and defines driving under the influence in terms of evidence and how it relates to proving that one was driving while intoxicated by marijuana. Evidential circumstances include, but are not limited to one’s driving behavior, field sobriety testing performance, conduct with the law enforcement officer(s), and drug test results. The California Legislature is debating a bill to consider any trace of THC as legal evidence for driving under the influence. This would do away with the Prosecutor having to prove that one’s driving was drug impaired, in order to achieve a conviction. As ongoing research attempts to demonstrate a standard with regards to an absolute amount of THC which impairs driving ability, there seems to be little legislative will to set a THC standard.