For several generations American roads have been dominated by motor vehicles. No one alive today can remember a time when non-motorized vehicles dominated the roads.
According to a history of automobiles I read recently, there were approximately 10,000 cars on the roads at the beginning of the 20th century. It only took a few decades for all of that to change in the U.S.
“The United States alone—where 25 million horses supplied most local transportation in 1900—had about the same number of cars just three decades later. The country also had giant industries to manufacture them and keep them running and a vast network of hard-surfaced roads, tunnels, and bridges to support their conquest of time and distance. By century’s end, the average American adult would travel more than 10,000 miles a year by car.“