Researchers at Stanford University have developed a “Potalyzer”-a device that can detect human THC levels, so cops can determine if a motorist is too impaired to drive. The hand-held device uses sophisticated biosensors to detect THC molecules in saliva.
Police officers will supposedly be able to collect a spit sample with a cotton swab and read the results on a smartphone or laptop in just three minutes. Using magnetic nanotechnology, a process developed to screen for cancer, the device can detect concentrations of THC in the range of 0 to 50 nanograms per milliliter of saliva.
The Satnford press release on the breakthrough, attributed chiefly to lead researcher Shan Wang, states: “While there’s still no consensus on how much THC in a driver’s system is too much, previous studies have suggested a cutoff between 2 and 25 ng/mL, well within the capability of Wang’s device.” A critical report on the development from Mashable notes that Paul Armentano, deputy director for cannabis advocacy group NORML, has expressed skepticism about the very concept of a “Potalyzer.” “We don’t have a consensus as to what levels of THC are consistently correlated with behavioral impairment,” Armentano said.
Colorado has set THC limits for drivers-five nanograms in blood content according to the state Transportation Department. Other states that have legalized have still no set limits. As Mashable notes, some have assailed the Colorado standard as arbitrary.
“Typically, if you have five nanograms in a regular smoker, you probably won’t see any behavioral effects,” Columbia University psychologist Carl Hart told the Atlantic.
“Whereas, with five nanograms in someone who’s never smoked, you might see a lot of effects.” Furthermore, the question of “Marijuana-impaired driving” is widely misunderstood.
A recent study from the National Highway Traffic Safety Administration found that high drivers are much safer than those who drive drunk. The Washington Post summarized the study thusly: “After adjusting for age, gender, race and alcohol use, drivers who tested positive for marijuana were no more likely to crash than who had not used any drugs or alcohol prior to driving.” It may be politically taboo, but it is science.