Almost every conversation about surface transportation finance begins with a two-part question: What are the “needs” of the national transportation system, and how does the nation pay for them? This report is aimed almost entirely at discussing the “how to pay for them” question. Since 1956, federal surface transportation programs have been funded largely by taxes on motor fuels that flow into the Highway Trust Fund (HTF). A steady increase in the revenues flowing into the HTF due to increased motor vehicle use and occasional increases in fuel tax rates accommodated growth in surface transportation spending over several decades. In 2001, though, trust fund revenues stopped growing faster than spending. In 2008 Congress began providing Treasury general fund transfers to keep the HTF solvent….