http://www.fhwa.dot.gov/policy/ohim/hs05/finance.htm
According to the chart "Funding for highways and disposition of highway-user revenues, all units of Government – summary", 59% of highway revenues in the US comes directly from highway users. A further 16% comes from investment income and bonds. 26% comes from property taxes, general funds, and other taxes.
According to "Transit operator receipts and disbursements for operations", on average, 34% of operating costs come from passenger fares.