The Congressional Budget Office (CBO) has projected that lawmakers will have to find an extra $100 billion in addition to the gas tax revenue to pay for a new six-year transportation bill.
In the absence of Congressional will to increase the gas tax for the first time in two decades to close the gap, President Obama has recommended that lawmakers use approximately $150 billion from closing corporate tax loopholes to help pay for the new infrastructure spending. Obama proposed a four-year, $302 billion transportation bill that he says would increase the annual road and transit funding by about $25 billion per year.
Corporate tax reform is considered unlikely to be approved, though, and lawmakers in both chambers have begun exploring other funding options.
House Republicans released a controversial proposal to tie transportation funding to cutbacks at the U.S. Postal Service. House GOP leaders said that eliminating Saturday letter deliveries would provide approximately $15 billion that could be used for at least one year of new transportation funding.