Scientists still seek a reliable DUI test for marijuana

This spring, 16 state patrol officers from Colorado and Wyoming took a couple days off their usual work schedule to do something special. They assembled in a hotel conference room in Denver. As instructed, they wore street clothes for their first assignment: going shopping at nearby marijuana dispensaries.
“It’s a brave new world,” said instructor Chris Halsor, referring to the years since Colorado legalized recreational marijuana.
There are now more marijuana dispensaries in C