More than a quarter of a century after Louisiana voters approved funding for 16 road and bridge projects, the list is far from done.

In addition, the costs of the work will take an increasing bite of Louisiana’s key transportation fund amid constant bickering over shrinking resources and demands for improvements.

The overhaul, which voters approved in 1989, is called the Transportation Infrastructure Model for Economic Development.

TIMED was supposed to be a pay-as-you-go road and bridge building plan, including construction of the John James Audubon Bridge, which links New Roads and St. Francisville.

But 26 years later, two of the 16 projects remain undone — both in the New Orleans area. Those two are anywhere from seven to 10 years away from being finished, state officials said.

Meanwhile, leaders have long since concluded that financing the improvements through a special, 4-cents-per-gallon tax was not enough.

The original price tag for the projects was $1.4 billion. The latest estimate is $5.2 billion.

“It is unbelievable,” said state Sen. Bodi White, R-Central, who is often involved in Baton Rouge-area highway projects.

As a result, the state is grabbing an increasing share of the 16-cents-per-gallon gasoline tax that is supposed to finance transportation improvements in Baton Rouge, New Orleans and elsewhere.

This year, that raid will total $21.6 million, just under 1 cent of the 16 cents, to pay the TIMED debt, according to figures from the state Department of Transportation and Development.

Similar raids will be needed for the next 27 years, topping out at $87.6 million by 2044, state estimates show.

One of the key reasons, current and former officials say, is that original cost guesses were wildly off the mark.

“It was ill-conceived,” said Sen. Dale Erdey, R-Livingston, a veteran member of the Senate Transportation Committee. “They told Joe Public that it would be a pay-as-you-go-type situation, and of course, that was totally off base.”

Neither DOTD Secretary Sherri LeBas nor other top agency officials held their current jobs when TIMED was rolled out.

Motorists pay 38.4 cents per gallon in Louisiana for state and federal gasoline taxes.

That includes 4 cents that was supposed to pay for the TIMED projects and 16 cents per gallon for ordinary road and bridge work, even as its buying power shrinks because of inflation.

However, TIMED has changed what the state spends on roads.

Senate Finance Committee Chairman Jack Donahue, R-Mandeville, said he started asking questions about TIMED when he entered the Legislature in 2009.

Donahue said he was flabbergasted by what he found, including ineptness in planning projects and budgets. “It would just kind of make you shake your head,” he said.

One of the two undone projects — the construction of La. 3241 between Interstate 12 and Bush in St. Tammany Parish — may be finished in 2022, said Jeff Burst, DOTD’s project management director.

Donahue said there has been talk of scaling back plans for the four-lane, 20-mile corridor.

“What they are doing is totally unacceptable,” he said.

Construction is estimated to cost $200 million, Burst said.

The other project still to be done is a new Florida Avenue bridge over the Industrial Canal in New Orleans. Burst said its tentative completion date is 2025.

He said the original scope of the project may be changed to be more “community sensitive.”

Burst said construction and other costs for that project are estimated to be about $350 million.

Aside from the Audubon Bridge, other TIMED projects that are done include the widening of the Huey P. Long Bridge; upgrades to the Port of New Orleans and New Orleans International Airport; and the widening of U.S. 90 between Morgan City and Houma.

Original cost estimates are not the only problems that continue to reverberate.

State transportation officials decided in the early 2000s to sell bonds yearly to accelerate work on the projects in hopes of finishing them in 2012.

“The program was kind of at a standstill,” said Ken Perret, a former top official of DOTD. “The only way we could accelerate it was to bond it.”

Perret said the view at the time was that growth in revenue from the 4-cents-per-gallon TIMED part of Louisiana’s gasoline tax would pay the costs.

“But what happened is the 4 cents is not generating enough,” he said.

The hope was to pay off the debt by the early 2030s.

The latest estimate is for payments to continue through mid-2044 — including more than $1 billion from the 16-cent portion of Louisiana’s gasoline tax.

Erdey said he is concerned about taking money for TIMED projects out of the 16-cents-per-gallon revenue that is supposed to finance road improvements that taxpayers statewide are clamoring for.

“The general public expected these projects to be done by now,” he said.

Follow Will Sentell on Twitter, @WillSentell. For more coverage of Louisiana government and politics, follow our Politics blog at http://blogs.theadvocate.com/politicsblog/.