» How Florida Highway Patrol troopers detect drugged driving,

LAKE WORTH — Florida Highway Patrol trooper Joseph Loffredo, who’s qualified as a “drug recognition expert,” told The Palm Beach Post last week that, unless there’s a fear of a medical condition, officers can’t pull over a person unless they see a violation of the law, or at least traffic rules.

They might see a motorist going well above, or dramatically below, the speed limit. Swerving in out of lanes. Driving too close to others. Making sudden accelerations or stops.

“Maybe their left-turn blinker’s on but they’re turning right,” he said.

Once the person has been stopped, the officer — who still doesn’t know what substance might be in play — looks for clues. Those that indicate pot: glassy or bloodshot eyes. Dilated pupils. Swaying or twitching. Slurred speech. Inconsistent statements. A marijuana odor. The presence of a pot pipe or other paraphernalia, or even an unfinished “roach.”

“If we ask them for their driver’s license and registration and they hand us their Visa and MasterCard, that’s another clue,” Loffredo said. And, he said, cars now are equipped with multiple cameras.

The officer then orders a series of physical tests: following a finger with the eyes. Walking heel-to-toe and turning. Lifting a leg and counting aloud. Tilting the head up and counting internally to 30 (impairment will throw off the sense of timing.) And often, but not always, the iconic fingertip to the nose.

The lifted leg test can be a “gotcha” because the trooper instructs the motorist decide which leg; a sober driver is less likely to hesitate in selecting.

In the end, Loffredo said, the officer makes a judgment call the driver is impaired; “it’s not to determine impairment by what.”