Kentucky’s governor Steve Beshear, Indiana’s governor Mitch Daniels and Louisville mayor Greg Fischer had set up the study in January after identifying the scope for cost savings. At the time, it was thought that changes to the project would save at least US$500 million.

“We are committed on both sides of the river to build these bridges as quickly as we can, at the lowest cost possible,” said Beshear.

The largest saving – US$800 million - would result from rebuilding the downtown Kennedy Interchange in place rather than moving it to the south. Eliminating flyover ramps and making other design changes on the Indiana interstate approach to the newly expanded I-65 bridges would save US$215 million. A third key saving would be to reduce the East End Bridge road and tunnel from six to four lanes, which would cost US$174 million less than the original plan.