The Pennsylvania Turnpike Commission is offering what amounts to "buy one, get one free," but it's not a deal for everyone.

Officials said a deal with private sector investors interested in building the remainder of the Mon-Fayette Expressway and Southern Beltway could include giving the builder sections of the toll road already open to traffic or under construction.

The giveaway would amount to about $1.9 billion in land, concrete, steel and toll equipment -- much of it acquired when the purchasing power of the dollar was stronger -- and all the planning, studies and engineering that have gone into the development over several decades in Fayette, Washington and Allegheny counties.

The builder also would acquire the ability to levy and collect tolls on the highways.

In exchange for what would be 57 continuous miles of the Mon-Fayette Expressway and the six-mile Findlay Connector, turnpike commission officials want a joint venture of companies or global investors to spend up to $5.2 billion to finish the final 50 miles of the highways.

Because state leaders have admitted there's virtually no chance of raising so much money through public funding, the commission will hold a special informational meeting in Harrisburg on Sept. 17 for parties interested in a public-private partnership to design, finance, build and operate the 24-mile northern section of the expressway -- or part of it -- and the two remaining sections of the beltway.

All cards will be on the table, turnpike commission Chief Executive Officer Joe Brimmeier said, and anything is possible.

"I'm going to tell these people [attending the special meeting] that this isn't your typical project, that they have a blank slate and they can be as creative as they want," he said. "It's a totally different deal than anywhere else in the country or world."

While this isn't the first time the commission and project supporters have proposed privatization as a way to complete the toll road expansion program in southwestern Pennsylvania, officials said dangling a $1.9 billion carrot covering 57 miles of limited-access highway may prove too tempting for the private sector to ignore.

The meeting has been timed as a convenience for people from around the world arriving early for the International Bridge, Tunnel and Turnpike Association's annual conference in Baltimore, which starts with committee and special task force meetings Sept. 18. Privatization has been a growing interest in the toll industry for years.

"We're not going to say, 'You bid on this, this and this.' It can be a joint venture or a piecemeal thing," Mr. Brimmeier said. "We want them to show us how we can get this job done. They have to take some risks too."

Such a deal could mean construction of the Mon-Fayette Expressway would not reach Pittsburgh as envisioned by the project's originators in the 1950s and as directed by the state Legislature in the 1980s.

Instead, if a venture were to find the Pittsburgh extension financially unfeasible, only the stem and one arm of the 24-mile, Y-shaped northern end could end up being built from the expressway's current terminus at Route 51 in Jefferson Hills north to Business Route 22 and the Parkway East in the Wilkins-Monroeville area.

Or maybe only the two arms of the Y would be developed as a tolled bypass to the congested Parkway East and Squirrel Hill Tunnel, leaving an eight-mile missing link between the Turtle Creek Valley and the rest of the expressway to the state line and Interstate 68 in West Virginia.

Or if nobody were to make an acceptable proposal, maybe the whole deal will be dead after years of controversy, despite advancing the project through planning, environmental and design phases.

"We have no preconceived ideas," Mr. Brimmeier said. "Maybe somebody just wants to build from I-79 to the Findlay Connector. Maybe somebody just wants to build the Squirrel Hill Tunnel bypass. Maybe somebody wants to do it all. Our objective here is to complete both projects."

Even if a public-private partnership meant building only parts of either the Mon-Fayette Expressway or Southern Beltway, he said, it would be politically easier to try to raise a fraction of $5.2 billion than the entire amount to finish the remainder.

"These highways are vital to the future economic development of our region," Mr. Brimmeier said. "I want to get them on the books before I leave here."

Other turnpike commission officials speculated about other possibilities:

• Eliminating the arm of the expressway into Pittsburgh, but building the arm through the Turtle Creek Valley at half the cost and combining it with the last two sections of the Southern Beltway, would create a high-speed alternate route to Pittsburgh International Airport rather than the Parkway East through the heart of Downtown.

• Developing the Southern Beltway as a separate facility and creating an express route to the airport from I-79 and the Mon-Fayette Expressway from a new interchange north of Finleyville could be a stand-alone project worth pursuing.

Federal environmental clearances are expected for the last two sections of the beltway in the near future.

With the passage of Act 61 in 1985, the state Legislature directed the Pennsylvania Turnpike Commission to build the Mon-Fayette Expressway and Southern Beltway, but without identifying or providing sufficient funding.

The federal government has contributed only about $73 million toward the project, or less than 5 percent, although the toll roads are required to meet the same safety and engineering standards as interstate highways, which are 90 percent federally funded.