Closure of a portion of the Parkway East outbound caught many drivers off guard yesterday afternoon as traffic backed up for miles and some drivers reported being delayed as long as two hours.

The portion of the parkway between Squirrel Hill and Wilkinsburg will be closed until Monday morning. Crowds coming into the city last night for the Phillies-Pirates game and the SkyBlast show afterward were forewarned to take alternate routes home or to get off the parkway before the Squirrel Hill tunnel.

"Things are pretty heavy," PennDOT spokesman Jim Struzzi said yesterday afternoon. "We haven't had an outbound closure for some time and people must not have gotten the message.

"Last time we had an outbound closure, we had a big delay."

The Pennsylvania Department of Transportation announced the closure ahead of time, as it did the inbound closures of the last several weeks. Mr. Struzzi said that, for some reason, people adapted better to the inbound detours.

Two lanes are open between Bates Street and the Squirrel Hill exit, where drivers must exit and reroute through East End neighborhoods before reemerging onto the Parkway at Wilkinsburg.

Mr. Struzzi said he did not have an estimate on the average length of delay, but one driver, a rabbi, called the Post-Gazette to say he was two hours delayed and would miss a ceremony he had driven from Cleveland to perform. He said he got on the parkway without seeing any signs.

"I don't see how he could have missed the signs," said Mr. Struzzi. "We have them up everywhere."

Road workers are replacing concrete, and the closure is scheduled to remain in place through 6 a.m. tomorrow.