Background Private Sector financing of roads goes back to the earliest days of the Republic, indeed into Colonial times. It began with moves to replace fords and ferries with bridges and to keep roads paved with stone. Ferry masters often got a bridge "charter" from the state, whereby in return for the commitment to build a bridge they were given a right to collect a toll for passage. All over America, bridges were initially privately financed, mostly by family companies. A few survive to this day, exemplified by Dingman's Ferry Toll Bridge over the Delaware River, about 55 miles northwest of New York City, in what has become the Delaware River Water Gap National Park.
The country's major highways were first built as toll roads. Local roads were built by 'levee' - a statutory obligation to contribute one's labor several days a year to fixing the roads, or to opt out by paying local government the equivalent daily wage rate so they could hire laborers. But the locals did not see why they should labor on behalf of far-away merchants on the highways. Tax revenues were usually unavailable. So roads used by long-distance traffic - highways - tended to be turned over to turnpike companies to maintain. They in turn paid maintenance and serviced the capital they had raised with a fee on users - a toll. Historians estimate that, in the 19th century, between 2,500 and 3,200 companies operated toll roads; and somewhere between 30,000 and 50,000 miles of road were tolled by those companies (Daniel Klein, Santa Clara University, California).
In states such as New York and Pennsylvania, the most common joint stock companies in the 1810s and 1820s were turnpike, toll bridge or toll road companies. Mountain states, including Colorado, Idaho, Montana, Utah and Nevada, were opened up to mining by toll road companies. There were surges, then periods of retrenchment. Toll roads competed with one another and with canals. In the 1830s railroads became competition and many toll road companies went out of business. It was so common for toll companies to build the major bridges that, in the unusual case where a government managed to find the funds the resulting bridges were often called government bridges. In St Louis, the Eads Bridge was financed by investors.
Two things changed all that. The scandals surrounding the building of the Brooklyn Bridge, and the availability of gas taxes pioneered in 1920 allowed governments to take over the building and financing of bridges. From the 1920s to the 1950s, a series of remarkable bridges, tunnels, parkways and expressways was built. The public authority model established by Moses and Tobin was widely copied across America and remains powerful today.
The gasoline tax pioneered in Oregon in the 1920s was quickly adopted by other states. The gasoline and diesel fuel tax was initially used to create "trust funds" dedicated to road construction and maintenance. For over half a century this proved to be the most viable means of financing new roads, especially as manual toll collection was more expensive to operate. However, since the years of the Nixon Administration, gasoline taxes and trust funds have been increasingly used for rail transit and environmental enhancements. Since maintenance and operating costs of highways have soared, little funding has been available for new highway capacity. As less of their gas tax money has gone towards improving infrastructure, the American public has become highly antagonistic toward any proposals to raise the gas tax - at all levels of government. Most gas taxes are set at a flat rate, not a percentage of prices, so inflation erodes the purchasing power of gas tax revenues. More fuel-efficient cars, including more use of diesel and hybrid engines, threaten to turn that erosion into a chronic decline.