CBO projects that, starting in 2015, the highway account of the Highway Trust Fund will have insufficient revenues to meet its obligations, resulting in steadily accumulating shortfalls. That projection is based on two assumptions: that the taxes whose receipts are allocated to the highway account will continue at their current rates (most of those taxes are scheduled to expire at the end of September 2016) and that federal funding for highways will increase at CBO’s projected rate of inflation. To avoid such shortfalls, lawmakers would have to enact legislation to reduce highway funding, increase dedicated tax receipts, transfer money from the general fund of the Treasury to the Highway Trust Fund (as has occurred in recent years), or undertake some combination of those approaches.
For more detail on CBO's most recent projections for the Highway Trust Fund, see Highway Trust Fund Accounts—February 2013 Baseline.
Sarah Puro is an analyst in CBO’s Budget Analysis Division.