A Washington State Patrol trooper intercepted a driver on May 2017 on the suspicion that the man was driving under the influence (DUI). When the trooper, along with a Lynnwood police officer, pulled the driver over at 176th Street in Lynnwood, he found the driver to be intoxicated – he was driving under the influence of marijuana – and sent his blood sample for a test.
Driving under the influence of marijuana is quite common in the U.S. But incidents like these raise an important point of whether tetrahydrocannabinol (THC) levels detected in drivers after consuming cannabis can denote their impairment level. THC is the active ingredient in marijuana. As per a 2016 AAA Foundation study, it is not easy to depict the level of impairment in a driver by measuring the THC level in the blood. The study said, “There is no science showing that drivers reliably become impaired at a specific level of marijuana in the blood.”
When the toxicology lab sent back the Lynnwood man’s blood results in July, it showed the 53-year-old driver’s THC level to be 270 nanograms. The blood test of the driver, booked for DUI, revealed a 54 times higher level of THC than the permissible limit. In Washington, the legal limit of THC is 5 nanograms per milliliter of blood and the legal age for purchase or possession of marijuana is 21 years.
Undeniably, the driver was at fault and qualified for a DUI arrest. Like alcohol, marijuana too can cause impaired driving resulting in crashes. According to data from the Washington Traffic Safety Commission, out of 499 fatal crashes in the state in 2015, 91 of them involved marijuana-positive drivers.
There have been several experiments to determine the effects of marijuana to ascertain whether it actually impairs drivers, just like alcohol. In 2013, the KIRO 7 asked volunteers to smoke marijuana and then put them behind the wheels to show how dangerous it was to drive when high on marijuana.
In the case of the Lynnwood DUI arrest, the tests results were accurate, according to Dr. Brianna Peterson, toxicology laboratory manager with the Washington State Patrol. “Yes, the method is fully validated just as we do for alcohol,” she said.
According to the researchers of the AAA study, there is no universal parameter to associate THC levels of a driver with DUI. “Drivers with high levels of marijuana in their system might not be impaired, while others with low levels may be unsafe behind the wheel,” they said.
It depends on an individual’s inner resistance to withstand the effects of marijuana use. Marijuana can influence people differently, and it is very difficult to devise THC blood level guidelines. Another problem with marijuana is that it is detectable in the blood for a few hours after an individual (infrequent user) consumes marijuana. “A blood draw often occurs up to two hours after the initial incident, meaning the THC concentration has significantly decreased,” said Peterson.
Hence, field sobriety tests are still important to gauge impairment in drivers. What is more important to understand is that marijuana impaired driving is also dangerous, just like alcohol. As recommended by the AAA, there should be padded training modules to help law enforcement officers detect pot-impaired drivers. As Peterson rightly said, “THC is capable of causing impairment in all people.”
Addiction to any substance is a menace, be it to alcohol, marijuana, opioid or an illicit drug, which can be fatal if not treated. Hence, the only way to overcome addiction is to seek immediate treatment. If you have a loved one grappling with an addiction, call our 24/7 helpline number 855-441-4405 or chat online for immediate assistance. Whether it is alcohol abuse treatment centers or any other addiction treatment you are looking for, help is just a call away. We have the best alcohol addiction treatment options available in the country.