The Indiana Department of Transportation is finding plenty of people who want to do a feasibility study of the Illiana Expressway.

At least six firms responded to INDOT's request for proposals to study traffic and projected revenue for the proposed toll road by Thursday's deadline, according to Shelley Haney, an INDOT spokeswoman.

The purpose of the study is to determine if it can be built and run as a "public private partnership facility" with no money from the state or federal government, according to a copy of the request for proposals obtained by The Times.

The feasibility study also will identify a preliminary corridor for the expressway.

On Friday, Keith J. Bucklew, INDOT director of freight mobility and traffic management, updated the Northwest Indiana Intermodal Task Force on progress on the study, which was mandated by the Indiana General Assembly.

The winner of the contract for the feasibility study will be selected Aug. 17 and is expected to be working on the project by October. Bucklew said the study should be completed by July 2009. The state can pay up to $1 million for the consultant's work.

The Illiana Expressway would run from Interstate 57 in Illinois to Interstate 65 in Indiana.

"They will be looking closely at vehicle counts and truck counts," Bucklew said. "We know those are very high up here."

Bucklew's comments also confirmed the state has backed off Gov. Mitch Daniels' "go-fast" plan for the 25-mile expressway. He said under the best of conditions, it would be about 15 years before the first cars and trucks whiz down the road.

The study also will look at the feasibility of building the road with two lanes running in each direction versus building it with four lanes in each direction with reserved truck lanes, Bucklew said. The first option would make it similar to I-65 from Merrillville to just outside Indianapolis.

Daniels' original proposal for the roadway had it running from I-57 to Interstate 94, in Michigan City. The part from I-65 to I-94 was fiercely opposed by residents in Porter and LaPorte counties, so it was dropped from the plan.

Daniels also wanted to have construction under way by the end of 2009 or beginning of 2010. Daniels said that aggressive schedule was only possible if it was built and run as a private toll road.

That plan was resisted in the General Assembly, which rebuffed legislation to authorize it.

In March, INDOT Commissioner Karl Browning laid out a more realistic timeline for the Times Editorial Board and elected officials, saying ground could be broken within seven to 10 years.