A Senate committee on Wednesday took the first key step toward approval of a two-year transportation spending plan, and then pledged to find the money to pay for it and seek a long-term solution to the nation’s transportation funding deficit.

The Senate Environment and Public Works Committee approved a plan to spend almost $80 billion for surface transportation, creating the core legislation that will be augmented by an additional $29 billion for transit and transportation safety.

The unanimous vote was celebrated by committee members as a bipartisan triumph in an era when party politics have paralyzed Congress and driven its public approval ratings to historic lows.

“The bill before us is completely bipartisan; therefore, no one is going to think it’s perfect,” said Sen. Barbara Boxer (D-Calif.), the committee’s chairman.

In a show of unity, several committee members said they would defer introducing potentially controversial amendments until the bill was taken up on the Senate floor.

The bill would consolidate federal transportation programs from almost 90 to fewer than 30. It also would vastly expand a federal loan guarantee and grant program that has been touted by Republicans as their answer to the Obama administration’s jobs proposal.

“This is a jobs bill and an infrastructure bill that is designed to succeed,” said Sen. David Vitter (R-La.), pointing to the Senate rejection of the Obama bill last week.

A $12 billion gap exists between what the Senate proposes to spend and the available revenue. That’s primarily because the 18.4 cent per gallon federal gas tax intended to fund transportation has been diminished by fuel-efficient vehicles and other factors, no longer providing the robust revenue it once did.

What to do about that has stalled passage of a long-term transportation bill since the last one expired in 2009. Meanwhile, Congress has funded transportation through a series of short-term extensions, frustrating state highway administrators who need over-the-horizon funding certainty before they embark on major construction or renovation projects.

“Everything we’re doing today is predicated on finding an additional $12 billion,” said Sen. James M. Inhofe (Okla.), the ranking Republican on the committee.

On the Senate side, that search will fall primarily to Sen. Max Baucus (D-Mont.), who chairs the Senate Finance Committee and also serves on the public works committee.

“I’ve got plenty of ideas,” Baucus said Wednesday, “and they’re bipartisan.”

One proposal that has been floated among some Senate Republicans is a well-head tax on newly drilled oil wells.

The Senate proposal would keep transportation spending at current levels, adjusted for inflation since the last bill was approved six years ago. The House, which initially proposed to curtail spending to match annual gas-tax revenue estimates of $35 billion, more recently has committed to keeping spending at current levels, and House Transportation Committee Chairman John L. Mica (R-Fla.) has said the House leadership also is searching for additional funding sources.

The senators whose staff crafted the bill approved Wednesday said partisan differences made for a daunting challenge. A key stumbling block was the transportation enhancements program, which mandates that states spend a portion their federal transportation funding on bike trails, pedestrian projects, landscaping and other things considered frivolous by Republicans in an era of budget cutting.

“This was a huge problem for us,” Boxer said. “There were moments where we almost threw up our hands. This was one of the toughest, toughest areas of negotiation.”

The compromise they reached will satisfy neither advocates for the program nor those who believe states should have unfettered authority to decide how to spend federal funds. The transportation enhancements program is included in the Senate bill, but far greater leeway is given states to determine how the money is spent.

The bill is a modest milestone in federal transportation spending because, for the first time since the 1980s, it contains no earmarks. There were 10 earmarks in the 1982 bill and the number exploded to about 2,000 when the last bill passed.

One of the most infamous transportation earmarks was “the bridge to nowhere” that the late Sen. Ted Stevens (R-Alaska) had funded at $233 million to build a bridge to an Alaskan island with only 50 inhabitants.