PITTSBURGH — PennDOT plans to raise the ceiling of the Squirrel Hill Tunnels in Pittsburgh in hopes of easing the bottlenecks the tunnels create into and out of city.

The tunnels carry Interstate 376 into and out of the eastern end of the city and haven't been rehabbed since 1980.

The $50 million to $60 million plan that will begin in 2012 is designed to raise the 13-foot, 6-inch clearance.

Trucks frequently hit the ceiling or come close, setting off sensors that stop traffic through the tunnels. That only complicates matters, because traffic tends to slow and back up through the tunnels even when there are no obstructions.

PennDOT spokesman Jim Struzzi says officials hope that by raising the ceiling and improving the lighting "people won't feel like they have to slow down" as they enter the tunnels.