The Congressional Budget Office, in one chart, sums up the looming disaster in the nation’s highway trust fund:  

The chart shows the yawning gap between projected revenue for highways and projected spending. That gap is set to grow thanks in large part to two factors: the fact that the gas tax wasn’t indexed to inflation and thus is stuck at 1993 levels, and improving fuel efficiency, which reduces gas tax revenue even further. The CBO says if the gas tax had been indexed for inflation in 1993, it would have gone from 18.4 cents a gallon then to 29 cents a gallon today.  

The choices facing Congress are simple, the CBO notes. Raise new revenue, cut spending or subsidize transportation programs from the general fund.  

Speaker John A. Boehner on Wednesday morning said the “hunt is on” to find a funding source for transportation. And President Barack Obama will talk about his budget’s $302 billion, four-year transportation plan on Wednesday afternoon.  

The White House said the president’s plan would plug the $63 billion hole over the next four years in the highway account, and that Obama wants to work in a bipartisan way to get the bill passed.