What’s next? On a whiff of marijuana, drivers could be tested at the side of the road.
New Scientist reports on a new saliva test for THC. If an officer smells marijuana after pulling off a driver, all it takes is a dab of cotton swab in the mouth, and 3 minutes later he has a result. This test is not done in a laboratory, but happens next to the road. The reading might reveal amounts so small that they are measured in Nano grams of THC thanks to a new test developed by Shan Wang at Stanford University in California.
The technology uses nanoparticles that fit perfectly with THC or reagents attached to a surface. If no THC is present in a motorist’s saliva, the reagent molecules transmit an electromagnetic distortion that can be measured by a sensor. If THC is added, there is less distortion. Wang says that the more THC is present, the weaker the signal will be..
This smart technology connects to a smartphone through Bluetooth making it easy to use on the road. No lab is needed. Wang thinks that the device will be tested in practice next, as he hopes to make it easy for law enforcement officers to use.
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The need for testing was made apparent by National Highway Traffic Safety Administration figures showing that between 2007 and 2014, the percentage of drivers with THC in their system escalated from 8.6 to 12.6 percent. Wang is not the only person in the breathalyzer, sweat measuring and saliva testing business trying to develop a test for THC. A better understanding of the drug is needed to formulate safe and consistent driving legislation.
There is no clear legislation on driving under the influence of THC, with twenty four states now allowing medical use of cannabis, and four allowing recreational use. Each state has a different law. Some have no law. Some have zero tolerance, while some set various different THC thresholds per milliliter of saliva.
Unlike in the case of alcohol in the blood, concentrations of THC in bodily fluids do not reflect how intoxicated a person is. The molecule can linger from 3 up to 10 days according to Redwood Laboratories. Heavy users can produce positive results up to 10 months after ceasing use. Depending on a person’s metabolism, the quantity and frequency of use results will differ.
According to an anonymous expert at the US National Highway Traffic Safety Administration, two developments will help clarify the situation. Firstly, accurate measurement of recent consumption is needed, and secondly, data measuring bad driving has to be collected and analyzed to find a correlation to the amount of THC in a person’s system and driving skill impairment.
In this regard, Wang’s idea to use saliva and nanoparticles for testing, might have potential, because it is an easily collected sample that can be analyzed quickly, and if it is accurate, measurements could be correlated to impairment, says the expert.
Cannabis drug testing
CBD oil contains such low levels of THC that it does not show on drug tests at all and would not affect your driving ability. Cannabis drug testing, and lack of suitable tests and agreed-upon intoxication levels, has caused legal debates in the past. It seems that defense lawyers might still have a field day on the matter, as the loopholes are not quite yet ironed out. The controversy is nowhere near solved.