A woman has been charged after her son called police to report that she may have been driving under the influence while he was in the car.

York Regional Police said they received a 911 call from a cellphone at approximately 4:30 p.m. on Wednesday.

There was no voice, but the dispatcher said it sounded like the call came from inside a vehicle. The dispatcher called back, and spoke to a boy who answered the phone.

"You can hear the boy, obviously scared for his well-being, in the car," York Regional Police Const. Andy Pattenden told CTV News Channel on Friday.

Pattenden said the boy was able to stay calm enough to tell the call-taker his name and age, as well as where he was. He also provided a description of the van and his address.

The boy's mother then got on the phone and told police she had only had one drink and that she was fine, officers said.

Officers were able to track the van to the area of Columbus Way and Mulock Drive in Newmarket. The van was pulled over, and the driver was placed under arrest. The boy was turned over to his father.

Police said a female driver was taken to a station in Newmarket, where officers conducted a breath test. Investigators said the woman blew more than twice the legal limit for alcohol, and was charged with impaired driving.

"It really is an unbelievable story...I'd call him a hero," Pattenden said.

"He was brave enough to pick up a phone and call 911 when he knew something wasn't right."

Officers said that York Regional Police have laid more than 1,500 charges for impaired driving so far this year, up from 1,384 charges at this time in 2014.

Police ask anyone who believes a motorist is impaired to call 911 immediately.

Anyone with more information in the case is asked to contact police at 1-866-876-5423, ext. 7141, or call Crime Stoppers anonymously at 1-800-222-8477 (TIPS).