BOSTON, Mass. (WHDH) -- A tractor-trailer traveling on Route 93 Southbound hit the ceiling of the O’Neill tunnel just after 9:30 Wednesday morning.

The tractor trailer had a flat bed with a box truck on top of it. The box truck caused damage to wires and light fixture. The initial traffic backup was minimal.

Damaged wires were removed and the truck exited the tunnel. All lanes were open as the investigation continued.