HARRISBURG -- "I'll let you in on a secret," Pennsylvania Turnpike Chief Executive Officer Joe Brimmeier told about 150 consultants, big road construction company representatives and financiers who filled a Holiday Inn auditorium near here yesterday.

"There's not enough money to finish the Mon-Fayette Expressway," he said, drawing smiles from the crowd that he hoped had someone with the deep pockets to accomplish what the turnpike cannot, along with two unfinished sections of the related Southern Beltway.

"Fifty miles [of the two toll roads] are up for grabs," he said. "We're asking you to create a team with financial capacity and technical expertise and come back with concepts and solutions" for a public-private partnership that will complete all or part of massive new highway network in southwestern Pennsylvania.

In exchange, the turnpike commission is willing to throw in for free up to 63 miles of expressway and beltway already built or under construction to the company or joint venture with an acceptable proposal.

It has been estimated that completing all remaining sections will cost $5.2 billion, including what engineers now say are 26 miles north of Route 51, Jefferson Hills, where the Mon-Fayette Expressway currently ends.

As Mr. Brimmeier and other officials explained, the private entity could offer to build only one section that it deems profitable, or build only part of the Y-shaped northern end to Pittsburgh and Monroeville, or a combination thereof.

"That would narrow the need for the amount of public resources needed to finish the rest of the system," Mr. Brimmeier said. "That would make it more palatable to the legislators" who would then have to decide the fate of and provide remaining funding for both projects.

"To accomplish our mission, we're asking you to think out of the box and be as creative as possible," he said. "We're giving you a blank slate. We want you to look at more than highways, but at gas and coal rights, greenfield and brownfield development, multimodal shipping using rails and rivers, pay park-and-ride lots and other opportunities."

The audience included major global investment and toll operators, including Goldman Sachs, Australia-based Macquarie Infrastructures and two Spain-based companies, Cintra and Abertis. The latter, teamed with New York-based Citi Infrastructures, has a $12.8 billion offer on the table for a 75-year lease of the Pennsylvania Turnpike.

The turnpike commission's "Requests for Concepts and Solutions" are due Nov. 11. After submissions are reviewed and evaluated, officials plan to solicit formal "Requests for Proposals" that could culminate in a deal or deals early next year.

Turnpike engineers offered six potential scenarios and future traffic projections for each one, based on computer modeling:

• Building the 13-mile section of the Southern Beltway from Interstate 79 near the Washington-Allegheny County line west to Route 22, Robinson, and the Findlay Connector that is already built and open to Route 60 at Pittsburgh International Airport.

• Building that section, plus the last section of beltway, an additional 13 miles from the Mon-Fayette Expressway near Finleyville to I-79.

• Completing two of the three legs of the Y-shaped northern section, between Route 51 and Monroeville, via the Turtle Creek Valley. The leg into Hazelwood, Bates Street and the Parkway East near Downtown would be abandoned.

• Completing two of the three legs of the northern section that would serve as a bypass of the congested Parkway East and Squirrel Hill Tunnel. The leg to Route 51 through Duquesne, Dravosburg, West Mifflin and Jefferson Hills would be abandoned.

• Completing two of the three legs between Route 51 and Monroeville, and the last two sections of the Southern Beltway, to create an outer beltway of Pittsburgh, including an alternative to the Parkway East and Parkway West to the airport.

• Building all remaining sections, a total of 52 miles, at a cost of $5.2 billion.

The public-private partnership has local support from a group called the Expressway Partnership Initiative. Formed mainly by the Mon Valley Progress Council and Monroeville Area Chamber of Commerce, it lists Pittsburgh Mayor Luke Ravenstahl and Allegheny County Chief Executive Dan Onorato as two leaders of efforts to complete the toll roads.