Despite repeated delays and surprises, the new Tacoma Narrows Bridge will probably cost $80 million less than expected, state transportation...

TACOMA — Despite repeated delays and surprises, the new Tacoma Narrows Bridge will probably cost $80 million less than expected, state transportation officials said.

The state won’t need all $800 million it was authorized to borrow to build the new bridge and renovate the old one because most of the money set aside for emergencies hasn’t been used, and some of the work will cost less than expected, state Transportation Secretary Doug MacDonald said Thursday.

The savings won’t affect the planned $3 cash toll, but it will shorten the amount of time drivers will have to pay tolls to retire the construction loan.

“We had contingencies in case it was far worse,” said Jeff Carpenter, bridge project manager for the state Department of Transportation. “But they didn’t manifest, and the public saved money.”

For example, transportation officials thought it would cost more to dispose of arsenic-contaminated soil from the old Asarco smelter. The state also will save money on its renovation of the old bridge by not replacing metal grates with lightweight concrete, as originally planned.

In 2002, the Legislature authorized the Transportation Department to borrow as much as $800 million to build the new bridge and fix up the existing bridge.

That borrowing authority worked much like a line of credit.

The department has borrowed a total of $669 million so far, said Amy Arnis, the agency’s deputy director of strategic planning and programming.

The DOT plans to borrow an additional $12 million to $14 million to pay more bills. Arnis said the final loan total has not yet been determined.