A state legislative committee Thursday authorized Louisiana transportation officials to pursue a $122 million plan to replace the Belle Chasse tunnel and nearby Perez Bridge using a public-private partnership.

The arrangement would be the first of its kind and could offer a new way to help tackle the state's $13 billion backlog of road and bridge needs.

The movable bridge was built in 1967. The tunnel, opened in 1955, is dubbed the car wash by local residents, because of leaks.

"The replacement is long overdue and it is inevitable," said Shawn Wilson, secretary for the state Department of Transportation and Development.

The plan was approved by the House and Senate Transportation committees without dissent.

Motorists use two southbound lanes through the tunnel on La. Hwy. 23 and two northbound lanes via the bridge.

About 33,000 travelers use the route daily across the Gulf Intracoastal Waterway.

Both structures would be replaced by a fixed span, four-lane bridge that could open in 2022-23.

The agreements, called P3s, involve the state putting up some of the money and private firms doing the building in exchange for a long-term revenue stream.

Tolls would also be used to pay for operations and maintenance.

One of the keys is whether the state can land a federal grant of up to $50 million.

That request was submitted to federal officials on Nov. 2 and state officials expect an answer by the summer of 2018.

Wilson said state officials have gotten interest from developers, contractors and financial firms.

The next step is for DOTD officials to craft solicitation documents that describe the scope of the project.

Those responses will be due by late 2018. A contract could be awarded in the summer of 2019.

Wilson said agency leaders want to get public input on the plans, including the willingness of residents to pay tolls.

Area lawmakers told the committee the response to the proposal has been generally positive.

Gov. John Bel Edwards has said the project would boost economic development on the West Bank of the Mississippi River.

La. Hwy. 23 connects to Interstate 910 in Gretna and, to the southeast, the Belle Chasse Naval Air Station.

The Legislature authorized public-private transportation projects in 2001.

Follow Will Sentell on Twitter, @WillSentell.