In 11th-hour negotiations before Tuesday's master plan vote, the Carnegie Science Center has dropped a demand for a pedestrian tunnel as part of improvements related to construction of the North Shore casino.

Despite the concession, the science center still hadn't reached agreement yesterday with casino developer Don Barden over improvements he would pay for to address concerns about the casino's impact on the facility.

Director Joanna Haas said the science center agreed to give up the request for the tunnel under North Shore Drive "in the spirit of compromise." It wanted the tunnel to protect pedestrians crossing between the science center and the UPMC SportsWorks complex after the casino opens.

"Our position is not a position of opposition to this project and we're trying to be reasonable," she said.

Bob Oltmanns, a spokesman for Mr. Barden and his company, PITG Gaming LLC, applauded the decision.

"I thought it was a very welcome compromise because we never believed it was an appropriate mitigating measure to begin with. We're really heartened to see them take another look at that," he said.

Ms. Haas and Mr. Barden renewed talks yesterday after the science center rejected offers he made Thursday to make improvements to address its concerns over bus access, lighting, pedestrian safety, landscaping and the location of a proposed hotel.

The effort came on the eve of an expected city planning commission vote Tuesday on the casino master plan, a first step toward eventual construction. The casino would be built next to the science center.

City Planning Director Noor Ismail would not say yesterday whether her staff is recommending approval of the master plan to commission members.

She did say that if it were to recommend approval, there would be conditions attached to the master plan with specific milestones for meeting them and at least some would relate to the science center's concerns.

"I'm certain that would be part of the conditions if we were to go forward with approval," she said.

The science center has threatened legal action if a master plan is approved without conditions addressing its concerns.

Ms. Haas said the science center still has been unable to get the commitments it wants from Mr. Barden on issues related to bus access, casino lighting interfering with the science center's observatory, and the location of a proposed casino hotel.

The science center did not get Mr. Barden's formal proposal until late yesterday afternoon.

While Mr. Barden has agreed to widen a service road at the edge of the science center property to allow for bus access, he has refused so far to widen Sproat Way on the other side of North Shore Drive, as the center wants.

He also won't put a traffic light at the location, saying the Pennsylvania Department of Transportation won't permit it because traffic volumes aren't high enough. If the center can convince PennDOT otherwise, he said, he would pay for the light.

Ms. Haas, who accused Mr. Barden of "cherry picking" from mitigation measures Thursday, said the proposed remedies regarding access work in tandem with one another. If one is removed, it could throw off the "overall success of the solution."

"It's the solution that we've been advised is the best solution, a workable solution, and the best thing we have to put forward right now and hold people accountable to," she said.

While the center has given up the demand for the tunnel, Ms. Haas said it would watch closely to ensure that adequate safety measures are put in place for pedestrians crossing at North Shore Drive.

Mr. Oltmanns said Mr. Barden and PITG Gaming are willing to work through the weekend to reach an agreement, though he doesn't view Tuesday's vote as a deadline. He said the ball is in the science center's court.

"I think it would be our intention to try to maintain whatever momentum we have in keeping this dialogue going before the planning commission [vote]," he said.

The Steelers and Pirates are pushing for a study of the casino's impact on traffic during Heinz Field and PNC Park game days before master plan approval.

They fear casino traffic could significantly increase the time it takes fans to get to and from games. However, their position seemed to get little support during a gaming task force traffic committee meeting Thursday.

While several members, including representatives from the Northside Leadership Conference and Allegheny West Civic Council, backed the idea of a comprehensive traffic study relating to the casino, they didn't think it had to be done before the master plan vote.

Robert Brooks, the Steelers traffic consultant, argued yesterday casino traffic could add two to three hours to pre- and postgame commutes. He said the study should be done immediately.

"I never heard of a development being approved without knowing the [traffic] implications and developing solutions," he said.