Transport officials say a Highway 30 overpass on Montreal's South Shore is safe, even though a chunk of it fell off Tuesday morning, shattering the windshield of a car passing underneath.

Two motorists were caught by surprise when a postcard-sized piece of the outer concrete layer protecting the overpass fell off in Brossard, shattered a windshield, and bounced off with such force it pierced the wheel of a second car.

The concrete laminate served esthetic and protective functions, but its deterioration shouldn't cause concern, said officials with Transport Quebec.

The accident happened where Highway 30 intersects with Highway 10.

Tests conducted on the overpass Tuesday indicate it is safe and sound, the agency said.

But repair work will be done in the next few days to strip off the laminate completely.

The Highway 30 overpass was built three decades ago.