Marijuana Breathalyzer in the Works to Identify Stoned Drivers

A handheld device that police could use to test drivers for the presence of THC is being developed by researchers at Washington State University.
PHotographer: Scott Harms

Stoners take note, police may soon have a tool to tell whether you're driving under the influence of marijuana. 

Researchers at Washington State University are developing a breathalyzer that will detect the presence of  THC, the psychoactive component of marijuana, the News Tribune reports. WSU chemistry professor Herbert Hill and a doctoral student are working on a handheld device similar to the ones used by police to tell whether a person is under the influence of alcohol. 

While driving while stoned is against the law in all four states—Washington, Colorado, Alaska, and Oregon—where marijuana has been made legal for recreational use, as well in those where the drug has been given the green light for medical use, police have had to rely on blood tests and traditional standardized field sobriety tests such as walking a straight line. A 2012 study found that just 30 percent of those under the influence of THC failed the standard sobriety tests, and the results of blood tests can take up to twenty-four hours. 

The THC breathalyzer will, researchers hope, give police a more immediate way to detect the presence of the drug. 

“We believe at least initially that it would lower the false positives that an officer would have,” Hill told the News Tribune. “They would have a higher level of confidence in making an arrest.”

On its website, the Colorado Department of Transportation warns drivers that they can charged with DUI for operating a car while under the influence of pot. 

Marijuana affects reaction time, short-term memory, hand-eye coordination, concentration and perception of time and distance. Getting high and getting behind the wheel of a car will get you arrested for a DUI – this law hasn’t changed with the legalization of marijuana in January 2014.

In the first full year after Washington legalized the recreational use of marijuana, the Washington State Patrol reported a 25 percent jump in the number of drivers testing positive for having marijuana in their system, the Seattle Times reported. Still, the number of crashes in the state stayed virtually the same as the year before.