HARTFORD, Conn. — In March 2016, University of Massachusetts psychologist Michael Milburn took an anti-marijuana op-ed in the Boston Globe as a personal challenge.
His state was five months out from legalizing marijuana, and Massachusetts Gov. Charlie Baker, State Attorney General Maura Healey and Boston Mayor Marty Walsh wanted people to vote “No,” saying there was no way to measure impairment from the drug, like police can do for alcohol.
“Well, wait a minute,” Milburn thought. “I bet I could do that.”
Three years later, uncertainty around enforcing drugged driving laws is still one of the loudest rallying cries against legalization in states seriously weighing bills on recreational marijuana sales. But Milburn says he has a solution — an app that measures your cognitive performance rather than the presence of different substances in your body.
“I’m calling for a paradigm shift in the way people think about impaired driving,” Milburn says.
The 68-year-old has spent $60,000 of his own money developing DRUID, which uses four quick tests to measure cognitive impairment. It’s being tested by police in Massachusetts, and used in marijuana research at Johns Hopkins, Yale, University of Colorado, Boulder and Washington State University.
Milburn recently learned the federal government intends to fund DRUID with $1.7 million, half going to his subcontractor, Johns Hopkins psychiatry professor Ryan Vandrey.
And the data they collect from ongoing research helps continually calibrate DRUID. Milburn envisions it being used one day by employers and people who want to self-assess their own impairment before they get behind the wheel.
How it works
Users start by getting their baseline score out of 100 by taking the tests a few times while sober.
There are three tasks that require users to do two things at once, like tracking a moving circle with their finger while they count the number of squares that flash on the screen. These test reaction time, decision-making and divided attention. The last task is pulled from the standard field sobriety tool kit, a single-leg stand, because disrupted balance is a strong indicator of impairment.
Baseline scores are usually about 35, while a score of 55 lines up with the standard impairment level for alcohol, a blood alcohol concentration of 0.08.
No marijuana Breathalyzer
What doesn’t work is measuring marijuana impairment based on the blood’s concentration of THC, the main active ingredient in marijuana. THC behaves differently than alcohol in the body, and can build up in the body fat of daily users, so a blood test may reveal a moderate level of THC even when they are not feeling its effects.
That’s a problem for state governments that have tried setting what are called “per se” limits, laws that prohibit drivers from having a certain level of THC in their blood.
The Governor’s Highway Safety Administration denounced these limits — which range from 1 to 5 nanograms of THC per milliliter of blood — in 2016, in “A Guide For What States Can Do” about drugged driving. A nanogram is one-billionth of a gram.