Leasing the Pennsylvania Turnpike for 75 years may not offer as big a bonanza as some officials have suggested.

Roy Kienitz, deputy chief of staff to Gov. Ed Rendell, said the administration expects forthcoming proposals to be "at the lower end" of estimates that have ranged from $12 billion to $18 billion in recent months.

That's far less than the $30 billion figure bandied about by some Democratic and Republican leaders only a year or so ago.

Nevertheless, if the winning proposal provides more revenue for roads, bridges and transit than the controversial Act 44 transportation bill, which includes raising turnpike tolls and converting Interstate 80 to a toll road, Mr. Rendell will push to lease the 360-mile east-west mainline and 110-mile Northeast Extension, Mr. Kienitz told members of the Pittsburgh Post-Gazette editorial board yesterday.

"Only when we open the envelopes will we know if the governor's proposal is the solution," he said. "It's going to come down to the numbers. If a lease provides more money than Act 44, then we have a compelling case" to present to the state Legislature, whose speedy approval will be sought.

Mr. Kienitz indicated that the administration expects no more than five major financial firms to bid for the right to operate and maintain the turnpike in exchange for toll revenues and, once current contracts expire, for profits generated by privately operated service plazas.

In similar deals made in 2005-06, a consortium of Australia-based Macquarie Group and Spain-based Cintra paid $1.83 billion to lease the 7.8-mile Chicago Skyway for 99 years and $3.8 billion to lease the 157-mile Indiana Toll Road for 75 years.

If a Pennsylvania Turnpike lease fetches $12 billion and the money were invested at an 8 percent rate of return, the state would net $960 million a year -- more than the $945 million per year over the next 10 years from Act 44, and without tolling I-80, a contentious issue.

Consequently, Mr. Rendell could win support for a public-private partnership from a large number of Republican members of the House and Senate who represent mostly rural communities in the 311-mile I-80 corridor across the middle of the state.

Mr. Kienitz said Mr. Rendell will announce results of the bidding within several weeks.

Meanwhile, the administration continues to work on an extensive contract setting operating standards, maintenance and other requirements to protect the interests of the state and turnpike users.

Proposed legislation to authorize a turnpike lease was forwarded yesterday to the Legislative Reference Bureau, where lawyers will draw up a detailed bill for legislative consideration if Mr. Rendell presses forward after the proposals are disclosed.

Mr. Kienitz and Chuck Ardo, Mr. Rendell's press secretary, have been visiting news media across the state, explaining a turnpike lease, promoting the governor's position and answering questions.

Mr. Kienitz talked about three segments of public opinion: people who think leasing the turnpike is a great or interesting idea, including those who want to keep I-80 as a free highway; people opposed to the idea, including turnpike commission personnel and beneficiaries of often politically based decisions; and people who just don't know or who feel uncomfortable about the idea of giving up public control of the historic highway.

Many in the last group don't like the idea of turning control of the highway over to foreign investors.

"[The high bidder] could be a company without a well-known American name but with American money, American investors and American know-how," Mr. Kienitz said. "Conversely, if it's an American firm, it will have foreign investors. We're dealing with top players in the world and they're all global companies."

If the bids are deemed a good deal for Pennsylvania, and if Mr. Rendell prevails in the Legislature, Act 44 will have to be modified. The bill includes the controversial 10 percent drink tax that Allegheny County Council enacted to support public transit.