At least two of the people treated at Lawrence + Memorial Hospital on Thursday during an unprecedented one-day spike in heroin overdoses were found in a vehicle, and AAA says the number of drugged drivers on the road is on the rise.

"While the number of drunk drivers is thankfully on the decline, the number of drugged drivers is headed in the opposite direction," AAA spokeswoman Amy Parmenter said in a news release.

Waterford Police Chief Brett Mahoney said police received a call about 3:30 p.m. Thursday of a possible overdose in a car.

An officer found the car on Clark Lane and pulled it over, Mahoney said, and found that one of its occupants, an unidentified male, had overdosed.

Though officers usually carry the antidote Narcan, the officer did not have it with him and summoned Waterford ambulance, Mahoney said. The ambulance company administered Narcan and took the patient to Lawrence + Memorial Hospital.

Waterford police have administered Narcan three times since they started carrying the antidote in November, and in all three cases, the overdose victims were found in vehicles, Mahoney said.

Deputy Chief Peter Reichard of the New London Police Department said one of the patients taken to L + M from the city Thursday was found in a car in a parking lot at Shaw's Cove.

"With the report today of an 'unprecedented' number of heroin overdoses in New London, AAA, state and local police are warning motorists that users don't just sit at home," said the news release from AAA. "They drive. And they could be in the car next to you. Or picking up their kids at your child's school — or at the mall."

Eight people were treated at L +M for heroin overdoses on Thursday, and a ninth person died from an an apparent overdose.

State, local and federal law enforcement officials are investigating to determine whether the overdoses were the result of tainted heroin or a particularly potent batch.

"Just this week I was notified about a fatal car crash involving a driver — not the victim — who police believe was on heroin," Parmenter said. "The drug is not just putting users at risk. It's putting everyone on the roads at risk as well."

Connecticut's crash data does not differentiate between alcohol impairment and drug impairment so at this point, most evidence is anecdotal, though traffic safety leaders are working to change that.

In the meantime, AAA is supporting the training of Drug Recognition Experts (DREs), a growing number of state and local police being trained specifically to identify — and help prosecute — drivers on drugs, according to AAA.

"Heroin use is not unique in just our cities. There have been heroin arrests in many cities and towns across the state," said Connecticut Department of Transportation's DRE Coordinator Edmund M. Hedge.

AAA is reminding motorists to drive defensively and to report any driver who appears to be impaired to police.

k.florin@theday.com

Twitter: @KFLORIN