The Senate is poised to debate and vote on a patch to keep the Highway Trust Fund solvent until a long-term program can be funded.

The question for debate is, how long will the patch last?

The main legislative vehicle is a House-passed bill that would provide $10.6 billion to keep the Fund going through next May.

But a bipartisan group of Senators is proposing an alternative that would cut off funding in December in order to force a quicker decision on a long-term bill. Joining forces to press that alternative are Sens. Barbara Boxer, D-Calif., Tom Carper, D-Del., and Bob Corker, R-Tenn.

“I’m on the Carper-Corker-Boxer amendment that would say instead of funding this highway bill through next year, get our work done this year,” Boxer said this week.

Among the supporters of this approach are the U.S. Chamber of Commerce and American Trucking Associations.

ATA believes that shortening the patch to December 19 will force Congress to act on the larger issue of sustainable, long-term funding for a highway program that is lurching from one temporary patch to another.

“ATA continues to seek an immediate solution to the impending insolvency of the Highway Trust Fund,” said ATA President and CEO Bill Graves in a statement.

“The December deadline provides the cushion needed to avert near-term funding interruptions for states and provides ample time for lawmakers to resolve the long-term challenge facing the Trust Fund,” Graves said.

The Senators pushing for a shorter patch want quicker action on a long-term bill but they also object to the funding mechanism that has been proposed for the patch.

That mechanism includes so-called “pension smoothing,” which uses a temporary lowering of pension funding requirements to increase business profits. Those presumed profits are taxed, producing a presumed increase in government revenue.

Sen. Corker said this approach uses 10 years worth of revenues to generate 10 months worth of funding.

“Pension smoothing increases the chance that the taxpayers will be on the hook for the bailout in the future because it weakens the corporate pension system,” Corker said.

“So here we are, weakening our balance sheet and simultaneously weakening the (Pension Benefit Guarantee Board). I hope we will … reject this irresponsible pay-for once and for all and do something far more responsible.”

At issue is the pending collapse of the Highway Trust Fund due to insufficient funds. Unless Congress acts, by the end of July the Department of Transportation will have to cut the flow of reimbursements from the Fund to the states.

States already have begun delaying or stopping projects to prepare for a possible shortfall. A cut-off would bring state projects to a full stop and throw hundreds of thousands out of work.

The Senate is occupied through Wednesday morning on another matter. The highway legislation is next on the legislative calendar.