The report documents that the amount that road users pay through gas taxes now accounts for less than half of what’s spent to maintain and expand the road system. The resulting shortfall is made up from other sources of tax revenue at the state and local levels, generated by drivers and non-drivers alike. This subsidizing of car ownership costs the typical household about $1,100 per year—over and above the costs of gas taxes, tolls, and other user fees.
While congressional bailouts of the Highway Trust Fund have made this subsidy more apparent, it has actually never been the case that road users paid their own way. Not only that, but the amount of their subsidy has steadily increased in recent years. The share of the costs paid from road-user fees has dropped from about 70 percent in the 1960s to less than half today, according to the study.
These facts cast new light on the widely agreed-upon belief that increasing the gas tax is politically impossible: What the reaction to this hike really signals is that drivers don’t value the road system highly enough to pay for the cost of keeping it in operation and maintaining it. Drivers will make use of roads, especially new ones, but only if the cost of construction is subsidized by others.
The conventional wisdom of road finance is that there is a shortfall of revenue—that the country needs more money to pay for maintenance and repair and for new construction. But the huge subsidy to car use has another equally important implication: because user fees are set too low, and because, in essence, people are being paid to drive more, there is excess demand for the road system. If roads were priced to recover even the cost of maintenance, driving would be noticeably more expensive, and people would have much stronger incentives to drive less, and to use other forms of transportation, such as transit and cycling. The fact that user fees are too low not only means that there isn’t enough revenue, but that demand is too high. One value of higher user fees would be that they would discourage excessive use of the roads, lessen wear and tear, and in many cases obviate the need for costly construction projects.