By serving travelers and commerce, roads and streets unite people and foster economic growth. But as they develop, roads and streets also disrupt old patterns, upset balances of power, and isolate some as they serve others. The consequent disagreements leave historical records documenting social struggles that might otherwise be overlooked. For long-distance travel in America before the middle of the 20th century, roads were generally poor alternatives, resorted to when superior means of travel, such as river and coastal vessels, canal boats, or railroads were unavailable. Most roads were unpaved, unmarked, and vulnerable to the effects of weather. Before the railroads, for travelers willing to pay the toll, rare turnpikes and plank roads could be much better. Even in towns, unpaved streets were common until the late 19th century, and persisted into the 20th. In the late 19th century, rapid urban growth, rural free delivery of the mails, and finally the proliferation of electric railways and bicycling contributed to growing pressure for better roads and streets. After 1910, the spread of the automobile accelerated the trend, but only with great controversy, especially in cities. Partly in response to the controversy, advocates of the automobile organized to promote state and county motor highways funded substantially by gasoline taxes; such roads were intended primarily for motor vehicles. In the 1950s, massive federal funds accelerated the trend; by then, motor vehicles were the primary transportation mode for both long and short distances. The consequences have been controversial, and alternatives have been attracting growing interest.
The story of the pre-Columbian Mississippi Period (1000