Accompanying Driving While Under the Influence (DWI/DUI) of alcohol laws in every state are prohibitions against driving while under the influence of a drug, which necessarily includes marijuana. While few would dispute laws that ban impaired driving while under the influence of any drug, an issue arises when lawmakers try to quantify the level of THC in marijuana that makes it illegal to drive a motor vehicle.
THC is the substance in marijuana that gives the drug its psychoactive effect. The substance has been the subject of the medical marijuana debate but has been accepted by many medical experts as useful in treating nausea and glaucoma and in stimulating the appetites of AIDS and cancer patients, among other reputed uses.
Colorado is among the first states to attempt to limit the amount of THC that drivers can have in their blood and still legally drive. Proposed House Bill 1261 sets the THC limit at five nanograms (ng/mL) or more in order for an individual to be charged with a DUI. The bill is being vigorously opposed by the Cannabis Therapy Institute, an advocacy group for medical marijuana that questions the correlation between the small amount of THC set forth in the bill and impaired driving.
The group has pointed out that a 2004 study by the National Highway Traffic Safety Administration reported that chronic marijuana or cannabis users typically demonstrate a much higher concentration of THC in their blood than five ng/mL and that this level does not necessarily cause impairment. There are 12 states with a zero-tolerance approach to the presence of any drug in a driver’s system, while Nevada and Ohio have a two ng/mL limit.
Medical marijuana advocates fear that the low THC level would inhibit medical marijuana users from using the drug since they will typically have much higher levels of THC in their blood. They also contend that medical marijuana users have developed such high tolerance levels that they are able to drive unimpaired at levels well above the proposed five ng/mL limit. Another concern is that the law will lead to medical profiling, as officers would concentrate on individuals known to use the drug for medical reasons.
The law’s proponents say that the legislation would not change how law enforcement approaches motorists. Further, someone would have to have smoked high-potency marijuana immediately before testing to achieve a level of five ng/mL. The bill is not yet in committee and is expected to stimulate much more comment in the coming weeks.
Source: Huffington Post “THC Limits for Drivers Proposed in Colorado Legislature,” 2/17/2011