Expert to Show Marijuana’s Effect on the Brain While Driving


With more and more states allowing for either medicinal and recreational marijuana sales, many fleets are beginning to show concern about whether or not they need to keep a closer eye on their drivers. No matter the controlled or uncontrolled substance a person imbibes, the effects on their driving ability and the safety of those around them on the highway is a cause for concern that needs to be addressed.

Dr. Denise Valenti, IMMAD LLC, will review driving and marijuana use in general and further discuss the associated dysfunctions to visual and neural pathways at the Fleet Safety Conference in Las Vegas on Wednesday, October 31, 2018. She will also provide additional information regarding the status of roadside testing related to marijuana impairment.

“Marijuana affects self-awareness. A driver cannot accurately self-assess so they do not judge their impairment properly,” says Dr. Valenti. “I compare this to the permanent dysfunctions with Alzheimer’s disease.”

According to the Washington Traffic Safety Commission, drivers testing positive for marijuana – active THC alone-indicative of use within four hours – in fatal crashes are six times more likely to have killed someone other than themselves compared to alcohol positive alone, as reported in the agency’s 2015 report “Driver Toxicology Testing and the Involvement of Marijuana in Fatal Crashes, 2010-2014.”

But how can we test drivers on the roadside? According to Valenti, there is a new possible test on the horizon.

“We have a National Institutes of Health National Institute of Drugs and Addiction Small Business Innovation Research contract to research a simple goggle virtual reality system coupled with a cell phone and blue tooth response button to measure retinal dysfunction,” explains Valenti. “We are finding mid peripheral vision impairments. This is essentially the ‘tunneling’ of vision often reported by marijuana users. The final version will be a quick, simple, objective, sensitive, specific test of marijuana driving impairment for law enforcement. This test will be threshold related and have a number value compared to a large normative data base. That test will take two minutes per eye.”