A new study from the U.S. Public Interest Research Group poses the question, “Do roads pay for themselves?” To save you reading 45 pages, their conclusion is no, they don’t.

The paper seeks to dispel the oft-repeated claim of highway advocates that roads pay for themselves due to gas taxes and other user fees assessed on motorists.

That’s a far cry from the truth, according to the study’s authors, who say that from 1947 to 2005, the amount of money spent on highways, roads and streets has exceeded the funds raised from gas taxes and other user fees by $600 billion. In fact, user fees charged to motorists only cover about half the cost of building and maintaining the country’s highways, roads and streets, according to the paper.

The authors, who include Tony Dutzik and Benjamin Davis of Frontier Group, and Phineas Baxandall of U.S. PIRG, write:

“Highways do not — and, except for brief periods in our nation’s history — never have paid for themselves through the taxes that highway advocates label ‘user fees.’ Yet highway advocates continue to suggest they do in an attempt to secure preferential access to scarce public resources and to shape how those resources are spent.”

Interestingly, their critique comes at the same time that transportation advocates have been fighting a Republican rule that they say could negatively affect the Highway Trust Fund, which is funded by the gas tax.

The paper goes on to suggest that the amount of gas taxes paid by motorists doesn’t necessarily correlate to motorists’ use of roads funded by the taxes. The authors also say highway advocates intentionally use “funding myths” to make public transit seem less viable and more expensive than highways.

They conclude that the “highways pay for themselves” model ensures that highway projects have a guaranteed funding source, regardless of whether there are priorities elsewhere, and allows transportation funding to be based on geography and other arbitrary factors.