AUGUSTA — While the City of Portland may have legalized the possession of amounts of marijuana less than 2.5 ounces, the state of Maine still considers possession of the drug a civil violation. Because state law pre-empts city ordinances – at least technically – nothing has changed. However, the Portland Police Department may decide not to enforce state law within the city limits, thereby implementing the intent of the city ordinance even under controlling state law.

It is likely that marijuana use will increase as criminal penalties for doing so are reduced or removed. Therefore, the risk of an increase in individuals operating motor vehicles while under the influence will likely increase as well. The ordinance shows increasing normalization of marijuana use across the nation. As more jurisdictions adopt similar laws, the possession and use of marijuana becomes more widely accepted, which has some potentially confusing consequences in the realm of OUI law.

NOT LIKE ALCOHOL

Operating under the influence as an offense is generally well known as it relates to alcohol. Everyone knows that a blood alcohol content of 0.08 percent is “over the limit” and will result in an OUI charge. But what about OUI of marijuana?

The effect of alcohol on the brain has been well studied, as has the body’s absorption and evacuation of the substance. Consequently, the legal system has accepted the tested wisdom that the degree of impairment correlates with the amount of alcohol in the blood stream, and that impairment decreases over a relatively accepted period of time. Moreover, the population generally has a rough idea of how many drinks are too many. However, the same knowledge does not exist for tetrahydrocannabinol, the active ingredient in marijuana. As a natural consequence of being illegal, marijuana’s THC content is not regulated. While a drinker will know just how strong his beer is by looking at the bottle, a smoker can never really know how potent a joint is. As a result, while the average drinker may cut himself off at one beer and expect to be under the 0.08 limit, the average smoker can’t make any such determination. Further, given the uncertain degree of impairment caused by THC, the smoker’s self-analysis of his impairment may itself be impaired.

The correlation between marijuana use and impairment is not as well studied as the link between alcohol use and impairment. Studies have shown that marijuana use increases impairment, but the degree is not well known. Studies have also suggested that regular marijuana use can actually decrease the impairment effect. As a result, it has proven difficult to craft per se laws for THC as we have for alcohol. States such as Kentucky, Colorado and Washington have, for many years, attempted to pass per se laws, whereby any driver found to have 5 or more nanograms of THC per liter of blood will be considered over the limit. These bills have faced considerable criticism because the amount of THC in a person’s blood is simply not an accurate indicator of impairment. Moreover, THC is fat soluble, whereas alcohol is water soluble. Consequently, THC remains in the body longer than alcohol, so a test of a person’s THC level may give a positive result but the person is completely unimpaired.

ONE TEST WON’T WORK

Law enforcement uses a series of roadside tests developed by the National Highway Traffic Safety Administration, called Standardized Field Sobriety Tests, to establish probable cause for testing a driver’s BAC. There are three – walk and turn, stand on one leg and horizontal gaze nystagmus (shaking of the eye when moving side to side) tests. If performed correctly, the SFSTs are intended to be 80 percent reliable when used together.

While the presence of horizontal gaze nystagmus has been shown to indicate alcohol impairment (with about 75 percent reliability), it does not show the presence of THC. Consequently, one third of the SFSTs do not apply for marijuana OUI stops.

Without accurate content information, smokers cannot know how much THC they have ingested, so they must rely on their own interpretation of their impairment to decide whether they should drive or not.

Similarly, deprived of a third of their battery of tests, law enforcement officers must rely more on their own interpretation of a person’s impairment when investigating a marijuana OUI case. Since drivers have less knowledge about what they are ingesting, and because law enforcement officers have to rely on subjective impressions, we may see significant increase in marijuana OUI charges.

— Special to the Telegram