Officials who want to build two new bridges over the Ohio River and redo a downtown interchange announced Thursday that they've found ways to cut the cost of the project by more than $1 billion.

The project joins Kentucky and Indiana in an effort that supporters from both states say is crucial to the region's economy.

"Building them as fast as we can using smart, cost-effective designs will produce the best value for taxpayers and motorists alike," said Indiana Gov. Mitch Daniels, who was unable to attend a news conference.

Kentucky Gov. Steve Beshear and Louisville Mayor Greg Fischer were there and said savings had been found that would lower the estimated cost from $4.1 billion to $2.9 billion.

"We have brought it to a size and a scope that is doable," Beshear said.

The project includes a new span into downtown Louisville and one to the east that would connect Prospect, Ky., and Utica, Ind. It calls for rebuilding Louisville's Kennedy Interchange, a web of intertwined ramps commonly referred to as "Spaghetti Junction."

With the scaled-down costs, officials hoped to build more momentum for the long-planned project.

But Beshear said the possibility of using tolls to help pay for the new bridges remains "very much on the table."

For months, the panel charged with financing the project has floated the idea of tolls on new and existing bridges as a way to pay for the new spans and a redesign of the junction where interstates 64, 65 and 71 converge near downtown Louisville.

The prospect of tolls has drawn some public opposition. Paul Fetter, co-founder of a group that says it has collected thousands of signatures on petitions opposed to tolling, praised political leaders for shaving the project's costs

"We may possibly be at that point where I-65 may not need to be tolled," he said. "We will continue our efforts until that is achieved."

Beshear said no decisions have been made. Kentucky and Indiana officials will compare the slimmed-down plan to two other options.

But Beshear said he remains "dead serious about getting these bridges built," and said Daniels and Fischer are equally committed.

Fischer predicted that even deeper savings could be achieved. Low interest rates will lower borrowing costs, he said, and bidding should be hotly competitive among construction firms eager for a piece of the project.

"We've been talking about these bridges for far too long," Fischer said. "It's time for some action."

Officials have eyed starting construction of the new bridges in August 2012. Beshear conceded that's an aggressive start date but said "we've got to be aggressive."

The officials said Thursday that the biggest chunk of savings would come from rebuilding the Kennedy interchange in its current place rather than moving it to the south. That alone would save $800 million.

Design changes to Interstate 65 in Southern Indiana would yield another $215 million in savings, and reducing the East End bridge from six to four lanes would produce $174 million in savings, they said.

Kentucky Transportation Secretary Mike Hancock said projected traffic volumes show six lanes wouldn't be needed for a long time.