This week, a committee in the Colorado House approved a five-nanogram standard of legal impairment. Like in Washington, the minimum level of active THC in a person's bloodstream would be set at 5 ng per milliliter of blood equivalent, above which law enforcement personnel could arrest an individual on charges of driving under the influence. Such a standard would operate much like the .08% blood alcohol content level for drunk driving and take much of the guesswork out of whether or not a suspect is impaired.
The decision to pursue the 5 ng standard was delayed for over a month amid opposition by medical marijuana advocates, who claim that users might be classified as impaired even though they hadn't smoked pot. But the Colorado measure provides an avenue for people accused of marijuana-related DUI to argue that they were sober despite a test result of 5 ng or higher.
The bill now moves on to the full house, where it could come up for a vote as early as this week. Of course, it will still have to get the thumbs-up from the state Senate as well as Colorado's governor before the proposal would become law.