BATON ROUGE -- The biggest question hanging over the upcoming debate on raising Louisiana's gasoline tax is whether backers can muster enough votes to get a plan through the state House.

After years of complaints, inside and outside the State Capitol, there is little disagreement on transportation needs.

Motorists in the Baton Rouge, New Orleans, Acadiana and elsewhere know firsthand, every day, what it is like to live in a state where road, bridges and other forms of transportation are in dire need of repairs.

But none of that matters if supporters cannot first get a tax hike through a crucial House committee vote, then garner at least 70 votes -- two thirds of the body -- in the Republican-run House.

State Sen. Bodi White, R-Central, twice saw his plan to create a new school district in southeast Baton Rouge sail through the Senate and House committees before dying in the lower chamber. "Seventy is a tough vote in the House," said White, a former House member.

The two-month legislative session begins on Monday at noon.

State Rep. Sam Jones, D-Franklin, who is sponsoring a bill that would raise the gas tax by 10 cents per gallon, echoed White's views. "Clearly, a great majority of folks in the Legislature don't like voting for tax bills," said Jones, whose measure would require a public vote.

Backers of raising more money for transportation have built their case for months.

A panel named by Democratic Gov. John Bel Edwards, himself an advocate of new aid for roads and bridges, recommended a $700 million annual hike for transportation, with the gas tax the key source.

Rep. Steve Carter, R-Baton Rouge, and others plan to file bills by the April 18 deadline that would increase the state gasoline tax.

A $500 million increase -- adding 17 cents per gallon -- is considered the best case scenario by supporters.

Motorists pay 38.4 cents per gallon now, including 20 cents in state taxes.

The state has an often-cited $13.1 billion backlog of rank-and-file needs, plus the need for another $16 billion for bigger projects, including a new bridge across the Mississippi River in Baton Rouge.

However, the drive to overhaul Louisiana's roads and bridges is coming to a head at a less than ideal time for backers. Not only is the state facing another budget shortfall.

The fact the governor is pushing a separate, controversial tax overhaul of his own, and is locked in an ongoing feud with Louisiana House leaders, makes prospects for a gas tax increase even murkier.

In addition, there are recurring complaints from key leaders that the state Department of Transportation and Development is doing a poor job of using current dollars, and that changes are needed before any tax hikes.

In a statement, the governor pushed back against the view that DOTD is the problem. "Since taking office, my administration has done exactly what the people wanted -- used transportation dollars to solve transportation issues and bring money back from Washington, D.C.," Edwards said.

But if a gas tax hike reaches the House floor, how exactly do backers round up at least 70 votes to send a plan to the Senate, where prospects are brighter?

Advocates say they likely have 50 or so votes, including heavy, but not total support from House legislators representing the traffic-choked Baton Rouge, New Orleans, Lafayette and Lake Charles areas. Another 12 or 15 lawmakers are unlikely to endorse any tax increase, which leaves roughly 40 legislators in play for backers to round up at least 20 "yes" votes.

Doing so is easier said than done.

Edwards plans to endorse gas tax legislation rather than offering his own, officials said, to avoid bogging down the issue by becoming a lightning rod for GOP criticism.

Rep. Jim Morris, R-Oil City, who earlier considered filing a bill for a significant gas tax boost, said Friday the votes for passage are not there, at least not now. "I don't think it matters how many pennies," Morris said.

Earlier this week 22 heavy hitters, including the Baton Rouge Area Chamber, the Louisiana Chemical Association and the New Orleans Chamber, called for at least $500 million in new transportation dollars, mostly through higher gas taxes.

Submitting any tax increase to voters -- it also requires 70 votes -- is considered a fallback position by transportation supporters. Any such campaign for passage would cost at least $2 million, they said, and approval would be anything but certain.

However, before any full House vote, advocates of higher gas taxes have to get a bill through the powerful House Ways and Means Committee.

Rep. Neil Abramson, D-New Orleans and chairman of the panel, is sponsoring bills, with Morris, that would require a wide range of steps aimed at making DOTD more efficient and transparent. "I think the first focus of our transportation needs is restoring confidence," Abramson said.

Whether action on those proposals -- House Bills 447 and 598 -- or similar measures trigger a fatal delay in action on revenue-raising measures remains to be seen.

Transportation advocates note that, because of legislative rules and key elections in 2019, any push to boost transportation spending likely would be delayed until at least 2021, if nothing happens this year.

DOTD Secretary Shawn Wilson, the governor's point person on transportation, said the debate should not end in Abramson's committee.

"I think this bill is so important that Ways and Means ought to advance it to the entire body," Wilson said. "I think at the end of the day the importance of not doing anything is so important that doing nothing is unacceptable."