One-third of all marijuana consumption is either eaten in food or ingested as a drink and the use of marijuana edibles has increased with the expansion of legalized recreational and medical use. The effect of THC (tetrahydrocannabinol), the main psychoactive ingredient in marijuana has been associated with an increase in traffic accidents and deaths, but unlike alcohol, no breath test exists for edible marijuana use.
Marilyn Huestis, PhD, from the National Institute on Drug Abuse, tested a roadside salvia test to see if it could accurately detect THC after eating marijuana in food. The on-site saliva tests were successful and offers advantages over traditional, time-consuming blood tests for drug screening.
Bottom line: Edible marijuana needs to be considered like alcohol, if you eat marijuana edibles it is wise not to drive.