The investigation continues after a single-vehicle crash on Highway 11 in the Powassan area last week.
Ontario Provincial Police from the Powassan detachment were dispatched just before midnight on May 4.
Police say a northbound commercial vehicle broke through the cable guardrails and rolled down a steep embankment.
The driver, who was the only person in the vehicle, suffered serious injuries and was transported to hospital by ambulance, according to the OPP.
The northbound lanes of the highway were closed for several hours after the crash.
