We're having something of a marijuana moment in the U.S. right now. Four states and the District of Columbia have passed laws legalizing pot for recreational use, and 18 others allow the drug to be used medicinally.
While that's great news for folks with glaucoma and/or the entire Phish catalog, it's creating some headaches for law enforcement. That's because there's no easy way for officers to gauge marijuana impairment like they do drunkenness -- at least not yet. Researchers at Washington State University are trying to change that with devices that analyze breath, much like the breathalyzers commonly used to measure sobriety.
The good news for WSU scientists is that the technology needed to achieve their goals already exists. The spectrometers that can identify THC -- pot's psychoactive element -- in a person's breath are very similar to those used for other things, like spotting explosives at airport screening sites.
The bad news is that the first versions of these weed-sniffing devices won't be very precise. WSU professor Herbert Hill says that they won't be able to determine the amount of THC present in a person's breath; they'll only indicate whether THC is there or not, which could lead police and other law enforcement officials to carry out additional tests.
The worse news -- at least for smokers -- is that the level of THC that classifies someone as "impaired" seems pretty arbitrary. In Washington state, for example, the law sets the bar at five nanograms of THC per milliliter of blood. However, anecdotal evidence suggests that many drivers perform well at far higher levels.
That said, the need for devices like these is rising, and as more pro-pot laws are expected to pass, need will probably increase. In Washington alone, the number of drivers who tested positive for THC shot from 18.6 percent in 2012 to 25 percent in 2013, after the state's law allowing recreational use went into effect.