U.S. Rep. John Mica released his vision for a highway bill Thursday that is wildly different from that proposed by his Senate counterpart, setting up a lengthy debate about the future of transportation funding.

In the coming months, the chambers will have to bridge major differences between the plans – amounting to four years of authorization and $20 billion in annual spending – or else Congress will have to continue to issue more temporary spending bills for the surface transportation programs. The previous long-term, surface transportation bill, SAFETEA-LU, expired in 2009. The country has been operating on short-term bills ever since.

In a briefing lasting nearly two hours, Mica, who chairs the House transportation committee, said he’ll introduce a six-year bill providing an average of $35 billion annually. Mica said his committee could begin hearings on his plan as soon as Tuesday.

That came on the heels of an announcement earlier this week from Sen. Barbara Boxer, who leads the Senate public works committee. She proposed, but has not yet introduced, a two-year bill averaging $54.5 billion per year.

The old SAFETEA-LU amounted to $244.1 billion over five years – or about $48.8 billion annually – meaning Mica’s plan provides 28 percent less funding each year, even before accounting for inflation.

During the announcement, Mica sought to portray himself as someone who would have preferred a more robust bill but whose hands were tied by his own party.

Earlier this year, House Republicans created a rule that would limit surface transportation funding to the revenues from the Highway Trust Fund, which gets most of its money from a gas tax of 18.4 cents per gallon. But the fund is struggling and is losing purchase power, since the tax hasn’t increased since 1993 and vehicles are becoming more efficient.

Meanwhile, House Republicans are playing a game of chicken over the debt ceiling as part of their long-standing goals of a major reduction in federal spending, which would likely make it even more difficult for a pricier package to emerge from that chamber.

“Those are specific rules of the House adopted by the [rules] committee,” Mica said. “I can wish I can jump over the moon, but I can’t do that either,” he added.

“I know folks would love to have a bigger… bottom line number. I’d like to have that too. We have to deal with the cards that are dealt.”

Mica, however, didn’t criticize his party and seemed to suggest the dollar amount of the bill was appropriate. “We believe we can do a lot more with less,” Mica said, adding that he believes states wouldn’t spend more money even if they were granted it, citing leftover stimulus money.

That's not how the states see it.

“We continue to have concerns about the proposed funding levels included in the bill, but we also realize that this is the start of a process that will include not only the House, but also the Senate and the Administration,” said John Horsley, head of the American Association of State Highway and Transportation Officials, in a statement.

The existing authorization for highway and transit programs expires at the end of the fiscal year on Sept. 30, so the House and Senate would need to pass and reconcile the Mica and Boxer bills before then. That's unlikely to happen. More realistic is yet another additional temporary spending measure for the surface transportation program. Those following the legislation say the length of the stopgap could signal how close the two sides are to an agreement.

The biggest obstacle to an agreement is the duration of the bills, not their cost, says Joshua Schank, head of the Eno Transportation Foundation and a former advisor to then-Sen. Hillary Clinton during the development of SAFETEA-LU.

While state officials have long said they need a six-year bill so that they can pursue long-term projects, some may be inclined to be more supportive of Boxer’s plan, or even a shorter extension, in hopes that funding prospects could improve with time.

But nearly all transportation experts agree: if the bill doesn’t become law this year, it likely won’t get done in 2012, as the election season tends to impede big legislation. To meet that timetable, the bills would have to emerge from both chambers by the early fall so they’d have to be settled in a conference committee.

The timeline is all the more difficult as the issue of the debt ceiling, along with 2012 appropriations, will increasingly eat Congress’s time in the coming weeks, says Sean Slone, a senior transportation policy analyst with the Council of State Governments.  “They’ve got to come together really, really quickly,” Slone says.

Mica’s proposal, like that of Boxer, includes, a plan to increase funding for TIFIA (Transportation Infrastructure Finance and Innovation Act), a program that allows state and local governments to borrow federal funds for their projects, from $122 million annually to $1 billion. Los Angeles Mayor Anthony Villaraigosa joined Mica's event remotely to praise the provision, for which he has advocated aggressively. L.A. would benefit enormously from a TIFIA expansion, as it would allow the region to accelerate a major transit expansion.

Mica's plan doesn’t include a national infrastructure bank, a proposal touted by President Obama and other some other senators. Instead, Mica said, the legislation would encourage states to expand their own infrastructure banks by increasing the amount of capital they could put into the programs.

Several aspects of Mica's proposal got high marks from transportation experts. They like its plans to accelerate the cumbersome federal approval processes that can delay projects as well as streamlining efforts to consolidate or eliminate 70 federal transportation programs. Mica said he would also increase the number of types of projects excluded from the National Environmental Policy Act (NEPA) process, and without elaborating on many details, Mica said the plan would include performance measures for state transportation projects.

"[Mica's] very constrained by what he can do funding-wise, but at least he's responding to the concern that the program had become unwieldy," says Greg Cohen, head of the American Highway Users Alliance.

The existing distribution of funding from the Highway Trust Fund – 80 percent for highways, and 20 percent for transit – will remain “pretty much” equal. Some transit advocates had hopes for a change.

Other issues remain unclear: what type of bonding mechanisms will be included in the legislation, whether it would create a Vehicle Miles Traveled fee pilot programs, and the details of a plan to allow tolling on new interstate lanes while prohibiting tolling of existing lanes.

(For more, view Mica’s plan here.)