Now that Massachusetts voters have legalized recreational marijuana, there’s still no simple way for law enforcement to test if someone is too stoned to drive.
“You have to prosecute the person based on the officer’s observations and what the officer found during the car stop,” William G. Brooks, president of the Massachusetts Chiefs of Police Association, told the Boston Globe. “It makes it very difficult.”
For that reason, University of Massachusetts psychology professor Michael Milburn is offering law enforcement an app that he funded and created to test for marijuana impairment.
Milburn calls his app DRUID, an acronym for “driving under the influence of drugs.” It is a tablet-based app in which users are asked to perform a series of tasks in five minutes.
The tasks include asking users to tap the screen in certain places when they see different shapes; to stop a clock when 60 seconds have passed; to follow a moving circle on the screen with a finger as it randomly changes directions; and to stand on one leg for 30 seconds each with the iPad in one hand.
“Prior to now, people had no way to really know if they were impaired or not,” Milburn said. “One of my hopes in this is to create a responsible community of drug users.”
Milburn ran tests and had his subjects use DRUID repeatedly while smoking weed; he tracked impairment scores as they rose, and then decreased as the pot metabolized in their systems.
How long does it take for that to happen?
To measure THC in the body, drug screenings measure carboxy-THC, a breakdown metabolite of marijuana. That process is affected by a number of factors, according to Paul Armentano, deputy director of NORML.
“The body’s excretion of carboxy-THC is influenced by the subject’s metabolic rate, percentage of body fat, and is also likely moderated by stress levels and diet,” Armentano explained.
So, in other words, everyone processes weed differently.
Experts agree that it’s not only the lack of a device to test drivers for marijuana impairment, there is also no accepted standard. In the case of booze, 0.08 blood alcohol content determines that a person is legally impaired to drive.
This quandary is partially attributable to the fact that, unlike alcohol, pot is fat-soluble and can be detected in a user’s body for weeks after use.
Milburn says that people who know they shouldn’t drive after smoking weed will get behind the wheel too soon because they don’t feel impaired.
The search to figure out who’s too stoned to drive goes on.
