Engineers Trying To Make A Reliable Cannabis DWI Test

Saliva test may help identify marijuana-impaired drivers

Engineers trying to make a reliable cannabis DWI test- As of November, seven states and the District of Columbia have now legalized marijuana for recreational. 19 other states have legalized medical marijuana. With an unprecedented number of States with legal access, concerns have been raised about driving under the influence of marijuana.

Research groups are now focusing on ways to identify drivers impaired by marijuana. At this time identifying recent use is not only difficult but creates wildly inaccurate results. Researchers at The Center for Medicinal Cannabis Research at the University of California, San Diego, are working to “gather data about dosages, time and what it takes to impair driving ability — and then create a viable roadside sobriety test for cannabis.”

The “Potalyzer”

A group of Stanford engineers has created a test called a ‘potalyzer.’ The effort was led by Shan Wang, Ph.D., a Stanford professor of materials science and engineering and  electrical engineering. His team of researchers developed a mobile device that detects the amount of tetrahydrocannabinol (THC) molecules in saliva.

The test would allow police officers to collect a saliva sample from the driver’s mouth with a cotton swab, analyze it with the new device, and then read the results on a smartphone or laptop in as little as three minutes.

The Stanford group focused on developing a THC saliva test because it is less invasive and may correlate better with impairment than THC urine or blood tests. Also key is the need for a very sensitive test. A Stanford news release explains:

Wang’s device can detect concentrations of THC in the range of 0 to 50 nanograms per milliliter of saliva. While there’s 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.

There is still a lot to do before police can deploy this ‘potalyzer’ device, including making it more user-friendly, getting it approved by regulators and investigating whether there is a better biomarker to detect marijuana impairment than THC. In addition, the test may not work well for THC edibles, the researchers wrote in a recent paper published in Analytical Chemistry.

On the upside, the Stanford technology could also be used to test for morphine, heroin, cocaine or other drugs — and for multiple drugs at the same time.

More research is needed, A new funding source is found in California’s marijuana legislation: Proposition 64 allots millions of dollars per year to research marijuana and develop ways to identify impaired drivers.


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