In the nearly 15 years since his son Dustin was killed at the age of 18 by a woman driving under the influence of alcohol and marijuana, William Church has been at the state Capitol working to change laws on drunken driving.

Now, he has a plea to legislators: Before deciding to legalize marijuana for recreational use, require a study to determine a way of detecting if someone's driving is impaired by its use.

While Church's reasons for advocacy are personal, he came to a hearing last week armed with scientific explanations and details of police procedures.

He talked about how unlike alcohol, THC — the psychoactive ingredient in marijuana — is stored in fat cells, and blood tests won't accurately reflect the impairment caused by cannabis use. He talked about the issues with Colorado's standard for measuring impairment. He talked about the fact that Connecticut has just 53 law enforcement officers trained as drug recognition experts, or DREs.

Church addressed the Public Safety and Security Committee last week, one of the last to testify in a six-hour hearing in which 46 bills were up for discussion. Specifically, he spoke on H.B. 5152, An Act Concerning a Study to Determine a Way to Detect When a Driver is Under the Influence of Marijuana. It would require the Department of Emergency Services and Public Protection to conduct such a study.

Unlike with alcohol, "there's no simple, accurate, roadside test to measure impairment," said Amy Parmenter, manager of public and government affairs for AAA in Connecticut. "And when I say that, I don't just mean that it hasn't been invented it; I actually mean that it's not possible."

That's because, she said, there's no correlation between the amount of active THC in someone's blood and the level of impairment in their brain.

In some states that have legalized recreational marijuana, lawmakers have tried to deal with this by setting a per se limit, meaning that anyone testing above a certain level is legally considered intoxicated.

Colorado and Washington have set a limit of five nanograms of THC per milliliter in blood. While this may seem analogous to the 0.08 blood alcohol content limit for alcohol, experts say it's arbitrary.

Parmenter noted that marijuana metabolizes differently with different people, so it doesn't make sense to use the same number to compare a regular medical cannabis user with someone who just consumed their first weed gummy.

Among police officers, drug detection expertise varies

The issue with setting a nanogram limit is that the level drops very quickly. This means police could make a solid DUI arrest only to have a blood test at the police station show less than five nanograms, explained Waterford Police Officer First Class Gil Maffeo, one of the 53 DREs in the state.

On the other hand, traces of marijuana can stay in the bloodstream for up to a month after the last intake.

Maffeo said in a phone interview that people from Colorado, specifically prosecutors, have told him they wish the state never set a nanogram limit.

"The best thing right now is to just better educate officers on recognizing the signs of impairment," Maffeo said. The most intense level of education is becoming a DRE, which starts with 72 hours of classroom training.

An officer must then correctly identify three different drug categories in 12 evaluations, some of which are hands-on and involve anonymous test subjects, and then pass a six- to eight-hour exam.

According to Willimantic Police Chief Rob Rosado, DRE training costs $5,000 to $10,000 per officer.

On the other end of the spectrum, every police officer must complete a minimum of four hours of training to conduct standardized field sobriety tests. Many of these tests are used to detect marijuana usage along with drunkenness.

There's the finger-to-nose test, for example, and one that involves asking the driver to stand with their head tilted back and eyes closed for 30 seconds.

"If they have a slow perception of time, that's an indicator that marijuana or some other drug can be onboard," Maffeo said. He said that it's a common misconception that people high on marijuana drive slowly, because people overcompensate for feeling slowed-down by speeding.

Maffeo would love to see more DREs, but he thinks the solution lies in the Advanced Roadside Impaired Driving Enforcement program, which bridges the gap between DRE training and the basic training.

Town of Groton Police Chief L.J. Fusaro said last week that the issue is establishing probable cause for arrest in the first place, because DREs are brought in to do additional testing after arrests, not before.

Legislation and technology reflect a search for some clarity

In explaining her introduction of the H.B. 5152, Rep. Gail Lavielle, R-Wilton, stressed that her bill neither supports nor opposes the legalization of marijuana.

She also clarified that the word "study" in the bill is not meant to suggest that Connecticut should be doing its own scientific research, but that it should review all available possibilities.

"If there is a legalization bill that goes someplace, I would hate to see it go without some provisions that provide for getting a better handle on this issue," Lavielle said.

The bill that would authorize and regulate the retail sale of marijuana has been referred to the Joint Committee on Finance, Revenue and Bonding, and a public hearing date has not yet been set.

Rep. Tom O'Dea, R-New Canaan, has introduced a bill that would prohibit a person with a concentration higher than 5 nanograms from driving.

Sen. Cathy Osten, D-Sprague, introduced a bill requiring "sufficient funds" to be appropriated "to fund the drug recognition expert program so that a sufficient number of state and municipal police officers will be qualified to identify drivers impaired by drugs."

Dr. Yifrah Kaminer, a professor of psychiatry and pediatrics at the University of Connecticut School of Medicine, told The Day there is technology to detect marijuana but "right now it's like computers in the '70s, the size of a big box in a room."

The California-based Hound Labs Inc. has developed a breathalyzer that determines if there is alcohol, THC or both in someone's system, USA Today reported. The company's research found that marijuana can be detected in one's breath one to two hours after smoking.

"The issue on the road, I don't think I have an answer," Kaminer said. "I don't think anyone has an answer."

Along with difficulties in detection, he also cites issues such as increased levels of THC compared to several decades ago, costs of dealing with the negative health and safety consequences of legalization, and risk of dependence, especially among adolescents.

Kaminer said of legalization, "It's like when you open a road, it's not paved, there's no traffic lights, there's no sidewalks, and you say to people, 'Oh, you can drive.'"

e.moser@theday.com