The brown Toyota that struck the man was travelling southbound through an intersection at around 2:30 a.m.
The traffic services officer ended up on the dashboard.
He was rushed to St. Michael's Hospital in serious but stable condition and suffered a broken left shoulder, left arm and left leg, said CBC videographer Tony Smyth, who arrived at the scene after the accident.
The officer's wife was brought to the hospital to be by his side, and Smyth said it was expected that the man, who has served with traffic services for three years, would face a lengthy recovery.
The officer's female partner was first to call on the radio for emergency medical services, Smyth reported, adding she told the dispatcher her partner was "lodged in the windshield" of the car.
"I do know that he ended up inside the car. Whether or not he went up over the hood or was airborne, that I can't say," said Const. Clint Stibbe. "That's for the collision reconstruction team to determine."
Stibbe said the officer had been with the police service for three years, and knew what he was doing.
"I know he was wearing a uniform. I don't know if he was wearing a safety vest at the time of the collision or not," Stibbe said.
Alcohol is not believed to be a factor in the crash, and the motorist whose vehicle struck the officer is co-operating with investigators, police said. Neither the driver nor his passenger were hurt.
Bathurst is closed in both directions from Lake Shore Boulevard to King Street, and the closure is expected to last for several more hours. Collision reconstruction experts will be investigating.