...No road pays for itself in gas taxes and fees. For example, in Houston, the 15 miles of SH 99 from I-10 to US 290 will cost $1 billion to build and maintain over its lifetime, while only generating $162 million in gas taxes. That gives a tax gap ratio of .16, which means that the real gas tax rate people would need to pay on this segment of road to completely pay for it would be $2.22 per gallon. This is just one example, but there is not one road in Texas that pays for itself based on the tax system of today. Some roads pay for about half their true cost, but most roads we have analyzed pay for considerably less.Read the full article at CommuteOrlando: Do Roads Pay for Themselves?
Overall, most roads cover about half or less of their costs from fuel and car taxes and fees in the US.
In other words, those of us who use less road surface (such as cyclists, pedestrians, transit users, stay-at-homes) subsidize road hogs. (Mass transit uses roadways more efficiently than cars do, and of course rail transit doesn't use them at all.)