You’re undoubtedly familiar with the breathalyzer, an electronic device that measures an individual’s blood alcohol content using a sample of his or her breath. In fact, if you are a licensed driver anywhere in the United States, you have given your implied consent to a breathalyzer test if you are ever pulled over on the suspicion of drunk driving.
Soon, you might also have to give implied consent to a breath test for recent marijuana use. A breath-based test that can measure the amount of delta-9 THC present in an individual’s bloodstream could be available sometime next year, according to researchers at Washington State University.
“This would be a more accurate test for them to determine whether someone is impaired, and combined with other evidence, whether they need to make an arrest,” said State Senator Mike Padden of Spokane Valley.
Currently, the same field sobriety tests that are used with suspected drunk drivers are used to gauge whether a driver is impaired by marijuana use. These tests include asking the driver to walk a straight line, stand on one leg, and the Horizontal Gaze Nystagmus, which asks allegedly impaired drivers to follow an object with their eyes without moving their heads from a stationary position. But marijuana does not affect individuals the same way that alcohol does, which is why a sobriety test developed specifically for stoned drivers is ideal.
Although driving after using marijuana is not as dangerous as driving drunk or driving distracted, using marijuana can still impair a driver’s ability to make safe decisions on the road. This is especially true if it is used in conjunction with alcohol.
In Washington, drivers are considered to be impaired if they are found to have at least five nanograms of delta-9 THC per millimeter in their blood. In Colorado, there is currently no legal limit for the chemical in drivers’ bloodstreams. Delta-9 THC is the psychoactive component of marijuana – it’s what gets you high. Developing a test that can specifically determine the amount of delta-9 THC in an individual’s blood is critical because it, unlike the metabolites that can stay in an individual’s bloodstream for days or weeks after using marijuana, can make a driver a hazard to other motorists and pedestrians.
But the test is not ready for use by law enforcement yet. Currently, it can only determine if delta-9 THC is in a subject’s blood – not how much. During its first round of trials, it was administered to 30 participants had an accuracy rate of approximately 50 percent. It also brought up one false positive, a sign that there is still a significant amount of refining to be done before the test can be released to the public.
“We don’t want to accuse somebody of smoking marijuana when they didn’t,” said Herbert Hill, a Washington State University chemistry professor who is part of the team developing the portable marijuana breath test. The test is currently undergoing its second round of trials and is slated to be available to law enforcement in about a year.
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