Ontario's police watchdog has concluded there are no reasonable grounds to lay charges against a Barrie police officer after a collision involving a motorcyclist last month.

The Special Investigations Unit says the officer had believed the way was clear when he made a left turn on a yellow light in Barrie on Aug. 21.

The agency says 44-year-old Albert Wayne Penfield struck the right rear passenger side of the police cruiser with his motorcycle. Penfield was taken to hospital with internal and pelvic injuries.

Acting SIU director Joseph Martino says it is unclear what colour the traffic light was when the motorcyclist entered the intersection, but it was at least yellow.

The agency interviewed four witness officers and seven civilian witnesses.

The officer involved was also interviewed and provided the SIU with his notes.

"There is no indication that the officer's driving was in any way substandard prior to the collision," said Martino in a statement.

"It simply appears that he did not observe the motorcycle entering the intersection and was surprised when it collided with the back end of his cruiser."

The SIU is an arm's-length agency that investigates reports involving police where there has been death, serious injury or allegations of sexual assault.