John Timpson of Narragansett had just started plowing the parking lot at Washington County Veterinary Hospital on Tower Hill Road in South Kingstown Saturday night when a white Volvo missing a tire drove in, nearly hit him, then pulled up into a snowbank.

Timpson, in an interview Monday, said the man — who turned out to be state Rep. Bob Watson, R-30, of East Greenwich — "got out and stumbled around a lot."

"I walked over to him," Timpson recalled. "He reeked of alcohol. I told him, 'It would be a good idea for you to call somebody.'

"I put the phone in his hand and he couldn't even call anyone," Timpson said. "I told him he wasn't going anywhere. My brother was with  me."

That's when Timpson decided to call the police.

Watson had told Timpson he had been in Richmond and was heading home to East Greenwich.

"He was heading in the wrong direction!" Timpson said. Tower Hill Road is divided. The only way to enter the Washington County Vets parking lot is by driving south.

Timpson and his brother were there when police arrived just before midnight Saturday. They finished plowing the lot at around 12:30 a.m., he said. Watson and the police were still there when the Timpson brothers left.

Watson was arrested for possession of marijuana, his second arrest in nine months. He was arrested in April 2011 for driving while intoxicated and marijuana possession in New Haven, Conn., and is awaiting trial on those charges.

Timpson said he was surprised that Watson had not been charged with driving while intoxicated. According to the police report, Watson was standing outside of his car when police arrived, rather than behind the wheel.

"How else would he have gotten there" except by driving, Timpson asked.

Watson entered a rehabilitation program Monday, it was announced.