Too stoned to drive? This app will warn you

An app designed to warn stoned drivers that they shouldn't be on the road mimics a traditional field sobriety test. PATRICK CAIN/GLOBAL NEWS

Figuring out how to deal with stoned drivers may be one of the biggest headaches that goes along with legalizing recreational marijuana — how to find them, how to test them, whether to set THC limits as we do for alcohol.

A University of Massachusetts psychology professor’s app looks at the problem from another angle — giving drivers a way of deciding for themselves whether they belong behind the wheel after smoking pot.

Druid, an app for iPhones and iPads, puts a driver through a series of tests that measure driving-related skills. The experience is like a simple video game, but the design resembles the field sobriety tests used for many years by police.

READ: Don’t legalize pot before figuring out how to deal with stoned drivers: poll

“What Druid does is provide a tool for those who actually want to be responsible,” explains Michael Milburn, its inventor.

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Performance-based tests measure impairment from multiple drugs, which measurement-based tests are bad at, Milburn explains. Moderate amounts of both pot and alcohol, in combination, can wreak havoc with the ability to drive.

READ: Marijuana use in Ontario on the rise, as is driving under drug’s influence: CAMH

“What seemed important to me was to measure actual impairment, as compared to just drug testing. It could be prescription drugs, it could be exhaustion, it could be marijuana or alcohol, or some combination, rather than just using a breathalyzer.”

WATCH: Const. Ian McDonald explains what the Abbotsford police is doing to crack down on drivers impaired by drugs.

Druid gives would-be drivers four tasks, which together take five minutes. The user has to:

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  • Play a game in which squares or circles appear on the screen, and respond differently, depending on which it is.
  • Estimate the passage of 60 seconds (push a button to start the timer, and another when they think the time is up).
  • Stand on one leg while holding an iPad, which is keeping track of how much they wobble.
  • Keep their finger on a circle that moves unpredictably around the screen, while at the same time counting squares that appear.

“One of the critical driving skills that is disabled by alcohol and marijuana is performance on divided attention tasks,” Milburn said.

“You have to look at the road, look at the speedometer, talk to the guy behind you, in the back seat. You have to be able to handle multiple things and not crash your car. Marijuana, as well as alcohol, interferes with that.”

READ: Pilot project for new drug-impaired driving test to start soon

Users go through the tests several times when sober, to establish their own personal baseline.

Milburn would like to see Druid used beyond stopping impaired driving.

“It could be used by sports team coaches to assess concussion risk. If there’s a collision, the coach could have all their baseline scores, and then say ‘Johnny, you need to do Druid before I can put you back in.’”

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A two-minute version and a release for Android are coming within the month, Milburn says.

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