The Pirates have fired another legal salvo in their battle over the North Shore casino.

They filed an appeal Thursday with the state Supreme Court challenging last month's approval by the city planning commission of the casino's foundation, steel and utility work. The Steelers, the other major North Shore sports team, previously had appealed the decision.

The project development plan approval enabled PITG Gaming LLC and its owner, Don Barden, to go ahead with the $450 million casino construction, although no work has started yet.

The Pirates and Steelers previously had appealed the planning commission's approval of the casino master plan.

Joel Aaronson, the Pirates' attorney, said the latest appeal was filed because of continuing concerns over potential traffic congestion resulting from the casino, particularly on game days at PNC Park or Heinz Field.

Studies by the team have estimated that casino traffic could add as much as 2¹/₂ hours to game-day commutes for Steeler fans and 90 minutes to those of Pirates fans.

"There's been absolutely no meaningful attempt to address the traffic chaos that's going to occur on game day when the casino's built," Mr. Aaronson said.

In their latest appeal, the Pirates said the planning commission's failure to get answers about traffic impact before approving the master plan and foundation and steel work -- and in other cases deferring traffic studies until after the casino opens -- "is tantamount to playing Russian roulette with the operational viability of the Pittsburgh Pirates and other major North Shore stakeholders like the Steelers."

The team said traffic studies should have been completed and proposed solutions agreed to before the casino construction was allowed to start.

Mr. Barden has been working with the city, the teams and other North Shore interests on a game-day study scheduled to be completed by Sept. 30. But Mr. Aaronson said he doesn't believe the scope of that study has been decided yet.

PITG Gaming spokesman Bob Oltmanns said the casino is working to finish the study by the end of the month and there's "no reason to believe we're not going to make the Sept. 30 deadline."

He added the casino believes the planning commission acted properly in approving both the master plan and the project development plan and "took into full consideration the numerous traffic studies that have been done since 2005."

"We're very sensitive to traffic on the North Shore and believe the mitigation measures we have proposed ... will be more than adequate to handle any additional traffic created by our business," he said.

Those measures include construction of a 3,800-space parking garage and an estimated $10 million in road improvements on the North Shore near the casino.

Neither the Pirates nor the Steelers are asking the high court to halt construction while the appeals are pending. Nonetheless, Mr. Aaronson said he hoped Mr. Barden would wait until the appeals are resolved to start construction, despite the developer's push to get the casino up and running as soon as possible.

In their appeal, the Pirates are asking the court to reverse the planning commission's decision or to appoint a master to conduct a hearing over whether PITG Gaming complied with zoning standards for project development plan approval.