AKRON, Ohio -- Two Ohio graduate students have invented a device that could allow law enforcement officers to determine whether motorists have used marijuana.

The Plain Dealer reports that two biomedical engineering graduate students at the University of Akron, Mariam Crow and Kathleen Stitzlein, developed a saliva test to determine the concentration of pot's active chemical, THC, in the bloodstream.

The students say that while states have set legal limits for levels of THC in drivers (less than 5 nanograms), they have not had the technology to accurately measure levels of the chemical during roadside police stops.

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"Today if a driver is suspected of impaired driving due to marijuana, law enforcement officers must call an Emergency Medical Squad to the scene or take the driver to a local hospital for blood work," Stitzlein explained in a university press release. "Lab results can take up to six weeks to come back, which is clearly not ideal."

The two women dubbed their invention "the Cannibuster." They received a $10,000 inventors' award and are hoping to market the testing device to states where marijuana use has been legalized.

Federal safety officials say driving under the influence of marijuana is a a growing problem. A National Highway Traffic Safety Administration survey, conducted in 2013 and 2014, found that the number of drivers with marijuana in their systems rose from 8.6 percent in 2007 to 12.6 percent in 2014 -- an increase of nearly 50 percent.

The report cited "evidence that marijuana use impairs psychomotor skills, divided attention, lane tracking, and cognitive functions" -- all essential skills for safe driving.