In one decade, cars replaced horses (and bicycles) as the standard form of transport for people and goods in the United States.
In 1907 there were 140,300 cars registered in the U.S. and a paltry 2,900 trucks. People and goods still travelled long distances on land by railroad, and short distances by foot or horse-drawn carriage. Almost nobody rode horses, but plenty of people rode bicycles for pleasure and for transport.
Ten years later in 1917, there had been a 33-fold increase in the number of cars registered, to almost 5 million, and a 134-fold increase in the number of commercial, agricultural and military vehicles, to almost 400,000. Horses were now an imperilled minority on the roads; bicycles were in decline in the U.S., although still popular in Europe.
Cars became popular because the price of these machines had plummeted: a Ford Model T sold for $850 in 1908 but $260 in 1916, with a dramatic rise in reliability along the way. Trucks became popular because businesses and the military (particularly during World War I) could make use of a reliable mechanical vehicle that could haul heavier loads farther and faster than a flesh-and-blood horse that required much care and maintenance and was limited to about 25 miles of travel in a day.
Machines for work, play and warfare: a tour through images from the pages of the Scientific American Archive from 1917.