In the wake of more states legalizing the use and possession of marijuana people are scrambling to come up with a definition of what categorizes “driving while high.” No one favors driving under the influence of marijuana or any other mind-altering drug. The problem becomes what exactly is the definition of driving while high and how do we test for it?
In Texas, if you are pulled over by law enforcement due to some overt cause such as weaving or erratic driving, the officer is going to suspect something is up. Currently, law enforcement uses field sobriety tests. The problem is that the equipment law enforcement uses to check for alcohol like a breathalyzer does not work for impairment by other drugs, specifically not for marijuana or THC. The only real solution at this point is to take the driver to the police station or hospital and draw blood.
Once police have the blood they can send it off to a lab to test if the person has marijuana in their system. But there are no legal limits in most states including Texas. Some states have set a standard at the limit of .5 milligrams of THC (the intoxicating substance in marijuana) per milliliter of blood.