With the arrival of the automobile, governments had to scramble to find ways to protect and control pedestrian use of the road.

Snowmobiles were invented around the same time as wheeled transportation was becoming a robust industry.

Traffic congestion has been a problem in the United States ever since the 1930s, and since that time, scientists have been studying on the problem.

The demolition derby was ready-made for the age of planned obsolescence from automobile manufacturers, who happily sponsored demolition derby venues.

In the 1920s car ads began changing. Specialists began to craft auto manufacturer's images solely to please their customers.

Henry Ford's newspaper, the Dearborn Independent, published years of anti-Semitic articles, prompting Hitler to call him the "single great man."