Driving under the influence -- whether of alcohol or drugs -- continues to be an area of concern. According to the Centers for Disease Control and Prevention, over one million drivers were arrested in 2016 for driving under the influence of either substance.
The agency also reported that marijuana use among drivers is on the rise -- increasing by 13 percent in the last year.
A new study that was recently published in De Gruyter’s Journal of Drug Policy Analysis explores the increase in driving under the influence of marijuana, as well as possible options available for testing THC levels.
Aiming for safety
As more states across the country legalize marijuana use, the researchers believe it may lead to more instances of people driving high. While there are several risk factors associated with driving under the influence, slowed reaction times and impaired depth perception and spatial judgment are some of the major concerns.
In addition to more stoned drivers, the researchers were interested in finding reliable ways to test drivers’ THC levels should they get pulled over. While breathalyzer tests are the most common -- and accurate -- way to determine a driver’s blood alcohol level, doing the same with weed proves to be more difficult.
The researchers suggested an oral fluid drug test as one such way to measure THC levels. This would involve getting a saliva sample from the driver and analyzing the drug levels. However, the report notes that these tests don’t measure specific levels -- just the presence or absence -- of drugs in the saliva.
An alternative would be a blood test, which would be able to assess how much marijuana is in the bloodstream. However, that would have to be performed by a trained medical professional in a medical facility -- which isn’t realistic for drivers getting pulled over on the side of the road. Additionally, the researchers note that THC levels drop rapidly in the blood, and would therefore pose the same concerns as the oral fluid test. It would be difficult to determine the level of impairment based on a blood test.
One potentially successful method would be a gaze test. The researchers explain in their report that several drugs -- including marijuana -- produce tiny movements in the eyes while the person under the influence attempts to stare straight ahead. While this method is still being tested, many law enforcement officials rely on field sobriety tests, which the researchers say can get tricky, or one of the chemical tests discussed above that may not produce the most accurate results.
Dangerous and illegal
Overall, the goal is to impress upon drivers that the risks associated with driving stoned -- especially when combined with alcohol and other drugs -- should not be ignored.
“Even assuming that an acceptable test can be developed, stoned driving alone and not including alcohol or other drugs, should be treated as a traffic infraction rather than as a crime, unless aggravated by recklessness, aggressiveness, or high speed,” said lead researcher Professor Mark A. R. Kleiman.