According to yet another great report from Jeff Davis at Transportation Weekly, House Republican leadership has given House Transportation Committee Chair John Mica permission to seek additional revenues to fund the transportation reauthorization at levels $15 billion higher than initially proposed.

One Republican source, quoted in Transportation Weekly, said that given the persistently high unemployment rates, the surface transportation bill may become the centerpiece of Republicans’ alternative agenda to the president’s proposed jobs bill.

The House reauthorization bill, introduced by Mica in July, followed the budget plan outlined in April by Rep. Paul Ryan, setting transportation spending at the level expected to come in through Highway Trust Fund revenues over the next six years. Transportation officials, advocates, and Democrats have decried those numbers as spelling starvation for the transportation program, especially for many innovative programs that have been introduced over the last few years.

The appropriations committee followed suit a few week ago, approving spending at those low levels. But by then, Republican leadership was reportedly having second thoughts. Jeff Davis writes:

House Republican leaders privately tried to dissuade the Appropriations Committee from moving a 2012 spending bill with the lower Trust Fund spending numbers, but it would have been awkward for the Speaker or Majority Leader to publicly criticize a Republican committee chairman for writing a bill at the budget level that 235 Republican House members voted for five months previously.

Sources say Mica and Republican leadership are seeking about $15 billion a year in additional revenues, providing a very significant boost to the spending outlined in the reauthorization proposal Mica released in July:

Adding $15 billion to each of those years could allow for spending totals above current baseline numbers of $41.6 billion for highways and $8.4 billion for transit in FY2012. However, it still wouldn’t quite match the Senate proposal, a two-year bill funding the surface transportation program at almost $55 billion a year. (The highway/transit split hasn’t been defined in the Senate bill.) Sen. Barbara Boxer says these levels essentially reflect current spending levels, plus inflation, plus an expanded TIFIA loan program.

Still, Davis writes, finding new revenues will be major challenge. A raise in the gas tax is reportedly off the table, and any new taxes would be difficult to pass – and not just because of the prevailing anti-tax sentiment in Congress. The Transportation Committee doesn’t control taxation, and Davis speculates that any new taxation would likely have to wait until after the deficit-reduction super committee finishes its work, two months from now. And any significant funding source outside of the gas tax and related “user fees” would be a dramatic departure from the traditional way of funding the transportation program.