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 shortly after 6:30 p.m.

The SIU says a provincial police officer had stopped a vehicle on the eastbound 401 at Wellington Rd. 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 the exit ramp to Veteran's Memorial Parkway and that the driver was taken to London Health Sciences Centre with serious injuries, including numerous broken bones.

The eastbound 401 off-ramp at Veterans Memorial Parkway was closed for the Police investigation for quite some time.

It reopened to traffic around 8 a.m. Sunday.

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.

The investigation continues.