Motorists are once again detouring around the outbound Squirrel Hill tunnel, which closed Friday at 11 p.m. and is scheduled to re-open 6 a.m. Monday.
Traffic is usually light on weekend mornings, said PennDOT spokesman Steve Cowan, until it starts backing up around noon.
The tunnel is slated to remain open in both directions for Memorial Day weekend and will then close inbound the weekends of May 31 and June 7.
The tunnel closures are part of a $49.5 million rehabilitation project that is scheduled to finish in the summer of 2014.
Correction, May 18, 2013: The cost of the rehabilitation project has been updated. It was incorrect in an earlier version of this story.
Anya Sostek: firstname.lastname@example.org or 412-263-1308.