Washington has legalized Marijuana: How does law enforcement identify if someone is driving under the influence.

It is common knowledge in the treatment industry that marijuana can be detected in the human body for as long as 45 plus days, there have even been circumstances of up to 90 days. This is not an exact science and individuals will metabolize the substance at different rates. The question becomes how we as a society identify if an individual is impaired. At what point is it unsafe to be driving or operating machinery after smoking marijuana. An appropriate test which determines a number or level appropriate for operating a moving vehicle was developed and being used in Washington with as much controversy as legalized marijuana itself.

Alcohol Metabolizes Similarly in Individuals

When operating a moving vehicle, alcohol has a limit of .08 parts alcohol for every 1,000 parts blood. Alcohol is processed quickly by the human body and in general this guide is appropriate for most citizens. There will be a very small portion of the population whose bodies metabolizes alcohol differently (A greater number that will try to contest this in court). In no way will this population hinder the reliability of the parameters with alcohol testing in law enforcement. Alcohol is water soluble and quickly metabolized at a cellular level riding the body of the substance.

Marijuana Metabolizes Differently in Individuals

Marijuana is much different. It takes longer to rid the body of the residual chemicals. This is not to say that the individual is impaired longer (This is debated) but it can be detected in the body for a longer period. Marijuana is fat soluble which can take up to 100% more time for the body to expel all remnants of this substance. There are studies that suggest a driver who is a heavy marijuana smoker will be impaired as long as a month after their last use. Other studies identify 3 to 6 hours as being an appropriate break to operate machinery. As with any statistic the possibility of individual bias can be present. If one is in favor of marijuana, research can be identified showing the safety of shorter durations of impairment, where one against could find research identifying the exact opposite.

Legalized Marijuana and “Legal Limits”

Washington has created a 5-nanograms-per-milliliter limit for active THC (THC stimulates cells in the brain to release dopamine, creating euphoria). The key word is active. This test measures the part that makes you high. The Non-Active is still in the system for the duration discussed earlier.

Here in lies the controversy. MOST people will fall below 5 nanograms after just a few hours of ingesting marijuana. Chronic users should be below the threshold within 24 hours but some might take three days. There have been cases of chronic users remaining above 5 nanograms after 15 days. There is also documented and published research that shows how the chronic user will remain impaired long after the visible 5 nanograms, up to three weeks of abstinence. It does not take long to identify the scientific, moral, societal and legal “can of worms”, opened by the proposition for legalized marijuana for non medical use in Washington.

Legalized Marijuana and DUIs

Safe to say that those who use legalized marijuana in moderation will most likely never have an issue with the current standard and legal limit, those who dare I say abuse the privilege might think twice before driving.

Irony: A great number of people who are proponents for legalized marijuana for non-medical use are chronic users. Chronic for the purpose of this article could be 4 times a day (My guess would be much more), these people will most likely test above the legal limit if stopped and tested. All others will simply test below. So the very people who led the fight of legalized marijuana will (If stopped and tested) be arrested for DUI.

Mark R. Kisner, MSW, CADC-II
(Disclaimer- In no way does this author believe all proponents are chronic users. Others are probably politicians, doctors, lawyers and even therapists)

If you or a loved one is struggling with marijuana abuse, Hired Power can help. We offer recovery assistance services as well as interventions. Feel free to contact us with any questions.