This chart is taken out of this amazing new report from the Pew Charitable Trusts, called Intergovernmental Challenges in Surface Transportation Funding. The report covers the challenges that are facing governments around road and transit construction and maintenance, paying especial attention to the shifting relationships between Federal, state and local funding streams.
For example, here are funding source ratios for different levels of government averaged across the US:
As you can see, the gas tax is crucial for Federal transportation funding. Note that this chart doesn’t reveal the different total amounts that come from these levels. Look forward to some of that information later in the week.
(Oh, also, user fees don’t pay for roads.)