As Congress prepares to reconvene and take up the payroll tax cut extension yet again, a movement is forming to restore the transit commuter tax benefit to 2011 levels.

Transit advocates across America were disheartened when Congress failed to maintain parity between the transit and parking pre-tax commuting benefits last month. On New Year’s Day, the maximum monthly pretax benefit fell from $230 to $125 for transit commuters, while motorists actually saw a slight increase in their parking benefits, from $230 to $240. (As The Sierra Club pointed out today, things used to be even more lopsided.) But members of the House and Senate have now indicated that a restoration is more than just possible, it could even be probable.

Rep. Richard Neal told Politico on Tuesday that a retroactive extension of 2011 tax policies is “likely,” and a staffer said today that “Nearly as often as extenders have been taken up in a calendar year, they have also been taken up retroactively.”

They won’t have to wait long for their first opportunity to prove it. In 54 days, the payroll tax cut extension expires, and Senator Charles Schumer and others intend to reinsert the commuter tax break at its 2011 level once it is reopened for debate. Speaking today in Staten Island, Sen. Schumer said he hoped to make the tax break permanent, and defended its inclusion in a tax cut extender bill, saying “it fits in the theme of a middle-class tax break.”

Schumer also said he hoped to make the tax break retroactive to January 1, but that could be difficult. It is true that precedents exist for retroactive tax cuts — there were plenty of retroactive cuts passed in 2010, including extensions of the Bush cuts to biofuel, payroll, and estate taxes – but it’s hard to un-buy a transit pass you’ve already purchased for January and started using.

“You can’t make it retroactive, but you can make it proactive,” explains Cathy Connor, Manager of Government Relations at Parsons Brinckerhoff. “January’s gone, and unless Congress passes the extender the day they come back, they can’t do February either. But it could still be good for March through December,” if not longer.

As for the benefit’s odds of being pro-rated for 2012 at all, Connor told Streetsblog, that depends on whether or not it becomes a “victim of the vehicle,” as it was in December. “There seems to be a lot of support in congress for it. If they decide to do a tax extender bill with just the payroll tax and unemployment, then that’s that. But if they open it up and start making it a more robust bill, this is a very meritorious provision that there’s a lot of support for.”