I thought this was interesting. The Texas highway department—Texas, no less!—says that roads simply don’t pay for themselves.
… 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. To conclude, in the SH 99 example, since the traffic volume for that road doesn’t generate enough fuel tax revenue to pay for it, revenues from other parts of the state must be used to build and maintain this corridor segment. The same is true across the state, meaning that, as revealed by the tax gap analysis, overall revenues are not sufficient to meet the state’s transportation needs.
There may be some political shenanigans at play here that, not being a Texan, I know nothing about. (Haven’t I heard that Texas is trying to build a massive toll-road corridor?) Still, the idea that roads don’t pay for themselves—and instead, must sap money from other funding sources—seems like quite an admission from a highway department. Perhaps there are lessons here for road construction projects all across North America, not just in Texas.