UPDATE (3:45 p.m.): Citing a lack of support from his colleagues, Speaker John Boehner has dropped his 18-month transportation proposal and has not yet offered an alternative, according to Politico. “A five-year bill is the best way to do this,” he said.

We’ve known for a few days now that the House, in the wake of Republican party infighting, was not likely to pursue a long-term transportation bill after all. It turns out, they’re not even pursuing a bill any longer than the Senate’s. But the House bill remains a drastic attack on programs for safer walking and biking while favoring highway construction and oil drilling.

Todd Zwillich at Transportation Nation broke the story last night that the House’s revamped transportation proposal will only authorize federal transportation programs for 18 months, running out in mid-2013. The Senate, meanwhile, has been working on a two-year bill.

The House leadership had to go back to the drawing board after factions within the Republican party came out against Chairman John Mica’s initial five-year, $260 billion bill, though for different reasons.

Moderates in transit-heavy districts opposed the elimination of dedicated funding streams for transit, and super-conservatives opposed what they saw as irresponsible deficit spending — even more so when one of their supposed funding sources, federal pension reform, wound up funding a tax cut extension instead, leaving an even bigger gap.

In its place, the House is proposing an 18-month bill that raises no additional revenue and continues to fund transit from the Highway Trust Fund. (There is no word yet on how much funding an 18-month bill would authorize.)

However, it still consolidates bike-ped funding out of existence, still gives states more authority to direct their transportation dollars towards highways, still rolls back environmental safeguards, and still ties infrastructure funding to expanded oil drilling. So while the changes may win over some undecided Republicans, they certainly haven’t made a decent piece of legislation.

Steve LaTourette, the moderate Republican and friend of Speaker John Boehner who has been a voice for multi-modalism, told Zwillich that the GOP leadership is still intent on taking the bill in an extreme direction. “They’re going to try to jam it,” he said. “They went backward because that’s what the conservatives said they wanted.”

House leadership has tried to pin the blame on Mica for the bill’s failures, prompting colleagues to rush to his defense. As Politico reported this morning:

“The chairman’s done a great job on this. In the last two highway bills the economy was good, the trust fund was flush. And we had earmarks,” Railroads Chairman Bill Shuster said. “This is like the chairman going into a fight with both hands tied behind his back.”

Meanwhile, Mica has in turn begun to take his frustration out on “public transportation people” whom he is now calling childish for defending the 30-year precedent of dedicated transit funding. He told Politico:

Even though we set up a separate fund and gave them five years’ funding, they threw their toys out of the playpen and said no, that this is unacceptable. They want to be in the fund that’s slowing diminishing. That’s the security that they’ve sought.

Mica must be in an awkward position, as he clearly has the House leadership to blame for hijacking and subsequently sabotaging the long-term transportation bill he had worked so hard for, even when Democrats controlled Congress. It’s understandable that he wouldn’t want to bash his bosses in public. But lashing out at transit riders? Where is the anger with the oil lobby, who no doubt encouraged so many of the bill’s dramatic policy changes? And where is the anger with the irresponsible unwillingness to let the federal gas tax keep pace with inflation — or at least to propose anything resembling a viable alternative?

Come an 18-month bill, a 24-month bill, or a 6-month extension, calling transit riders babies will not make Mica’s job any easier.