Police say a fatal single-vehicle crash on the QEW Thursday morning was caused by an object going through the driver's windshield.

Investigators said the 43-year-old driver lost control of his Toyota Rav4, struck the centre guardrail and then careened across all three westbound lanes into a wooded area near Mississauga Road after being stuck by an object.

Ontario Provincial Police said the Mississauga man was rushed to Oakville Trafalgar Hospital after being seriously injured in the crash, which happened around 8:15 a.m.

The man later succumbed to his injuries, according to police.

The westbound lanes were closed through the morning commute as police and fire crews cleared the scene. The Fort Erie-bound ramp to Mississauga Road also reopened following the collision investigation.

All lanes on the westbound QEW reopened shortly before noon on Thursday after an early-morning single-vehicle crash west of Toronto left one person dead.

Eastbound lanes were unaffected by the closure.

Investigators said they are probing the incident and appealing for any witnesses to contact provincial police.

With files from The Canadian Press