Plan to catch stoned drivers risks punishing innocent people, critics say

Studies find the “drug recognition expert’’ program lacks scientific validation.

Chelsea police Officer Paul Marchese, who has received “drug recognition expert’’ training, checked a driver’s license during a recent traffic stop. –Matthew J. Lee/Globe Staff

As Massachusetts opens more pot stores, Governor Charlie Baker wants to combat stoned driving by increasing the power and number of police trained to detect whether someone is high and a danger behind the wheel.

But defense attorneys and civil liberties advocates say the evaluation system that Baker is promoting, which relies on a series of observations by specially trained officers, is unscientific, deeply flawed, and could punish innocent people.

The “drug recognition expert’’ program, or DRE, has been rejected in numerous cases by Massachusetts judges who ruled it lacks scientific validation. Studies have found that the program’s claims of accuracy are overstated, and that it is biased and prone to false alarms.

Marchese held a device used to judge pupil size. —Matthew J. Lee/Globe Staff

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