LONDON, Ont. - Ontario's police watchdog is investigating a single vehicle crash in London.

The Special Investigations Unit says a 40-year-old man was injured in the accident early Saturday evening.

The SIU says a provincial police officer had stopped a vehicle on Highway 401 after receiving a traffic complaint, but it drove away as the officer was about to administer a roadside screening test.

Police say the vehicle crashed on an exit ramp a short distance down the highway and that the driver was taken to London Health Sciences Centre with serious injuries, including numerous broken bones.

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.