When 19 Connecticut and Rhode Island officers headed to the Police Academy in Meriden to become drug recognition experts, or DREs, two weeks ago, it was a Waterford police officer showing them the ropes.

With more than five years of related training himself, Patrolman 1st Class Gil Maffeo spent 80 hours walking the officers through the process of determining whether a person is intoxicated by something other than alcohol — or having a medical emergency.

It’s all part of a growing effort to combat drugged driving, a trend organizations including AAA say is on the rise.

Using the example of a driver whose blood test came back positive for THC, the psychoactive chemical in marijuana, Maffeo explained how the opinion of a drug recognition expert, or DRE, could complement test results in court.

“As a defense, (the defendant) will say, that’s from previous use” of marijuana, Maffeo began. “We come in and say, no, this person is impaired right now due to that drug. It’s psychoactive in their system. We write up a narrative and are allowed to render an opinion on their impairment.”

DREs follow a 12-step process after an arrest. They interview the arresting officer. They check the arrested driver's pulse, evaluate motor and language skills and ask about recently eaten foods to determine whether a medical issue has caused impairment.

Because certain drugs constrict pupils and others cause the pupils to dilate, DREs examine the eyes of the accused. They check a person’s muscle tone, too — some drugs make muscles rigid, while others turn muscles limp.

And those are just some of the steps.

Maffeo, one of four officers certified to train others to become DREs in Connecticut, signed on to the program not long after the state adopted it in late 2011. It was the 49th state to do so.

Maffeo said he was more stressed out trying to become a DRE than he was while completing a two-year master’s degree program. Trainees sit through about 80 hours, or two weeks, of classroom instruction before spending 40 to 60 hours in the field putting their newfound knowledge into practice.

In the classroom, they must score a minimum of 80 percent on three exams covering materials ranging from physiology to vital signs to information about the seven categories of drugs.

Once they’re in the field, students have to conduct at least 15 evaluations under the watch of a DRE. Toxicology results must corroborate at least 75 percent of their drug category conclusions. They’re tested again before they can move on. The recent group of officers Maffeo taught, which included members of the New London and Mashantucket Pequot Tribal forces, currently is in Arizona working on this hands-on phase at the Maricopa County Jail.

Trainees then head to a final, comprehensive exam — one that takes many of them five hours to finish.

“This is not a training where you can go and just sit,” Maffeo said. “You have to actively study. It’s intense.”

For Maffeo, his work is a calling of sorts. Early in his career — he started with the University of New Haven in 1999 before moving to Waterford in 2000 — a sergeant told him to find his niche in law enforcement.

He found that niche in enforcing intoxicated driving laws. With each stop he makes, he said, he could have saved the life of not only the driver, but also any others the driver may have encountered down the road.

“We all want to leave our mark in law enforcement,” he said. “I feel like I’m leaving that.”

According to state Department of Transportation DRE Coordinator Ed Hedge, officers who don’t attend the intensive DRE program receive similar instruction during a two-day, state-mandated course called Advanced Roadside Impaired Driving Enforcement.

“We’ve added a lot of drugged driving training to law enforcement in the past five years,” Hedge said. “We’ve literally trained hundreds of state and local troopers and officers in the two-day course and 31 in the three-week (DRE) course.”

Hedge said currently there are two DREs in Waterford and Norwich and one each in Montville, Groton Town and state police troops E and K.

The goal, he said, is to place at least one certified DRE in all of the state’s law enforcement agencies. In the meantime, though, officials are working to make it so there’s at least one available to respond to each department’s coverage area.

As for Maffeo, he hopes his instruction is inspirational for his students.

“I’m hoping I can get them to be as excited and passionate about something that’s 100 percent avoidable as I am,” Maffeo said. “Impaired driving: if people just didn’t do it, we wouldn’t need to do what we do.”

l.boyle@theday.com