Despite recent news of medical marijuana bills being approved into law in several states across the US, law enforcers are unsure about the implementation of these new laws.
Marijuana laws in Colorado and Washington specifically state that drivers are considered under the influence of marijuana if a test shows at least 5 nanograms of tetrahydrocannabinol (THC) per milliliter of blood. But unlike DUI cases involving alcohol, breathalyzers cannot be used by the police to measure THC — the psychoactive component in marijuana — in the bloodstream of suspected drivers.
Psychiatry assistant professor R. Andrew Sewell of Yale School of Medicine said in a news release that the relationship between THC levels and driver impairment has not been scientifically ascertained. Some people have a high tolerance for THC, especially those who have been smoking pot regularly. The limits of the law could only result in two things: the assessor can either miss the impaired driver, or apprehend someone who can actually handle the THC limit.
Procedures for testing THC levels in the bloodstream are made available for assessing drivers. A step-by-step assessment process developed by the International Association of Chiefs of Police involves an eye exam, and motor skills evaluation for the suspected user, such as the one-foot balance and a walk-and-turn test. However, only a small portion of the whole police force — less than 1% to be exact — are trained for this procedure to detect pot impairment.
Technology is still catching up to accurately detect marijuana use. The system of identifying alcohol-DUI cases in Washington is already one step ahead, as arrested or convicted drivers are required to install a vehicle starter device that detects alcohol from the driver’s breath. Law enforcers and legislators are hopeful that a similar technology can be developed for pot-DUI cases in the future.