Question

What spurred road building in the 20th century?

Answer 1

The development of automobile.

Answer 2

Answer:

The Automobile and its development  

The American Road became better as the cars that drove along it improved their engineering, roads had to be smooth and building took place throughout the 20th century.  

Explanation:

At first being able to drive a car was the novelty in the beginning of the 1900s but pretty soon the novelty wore off and people began to get angry at the bad bumpy roads. The government started to make the roads better in every state. All across the nation men and machines went to work the on the mud and this gave place to smooth pavement lanes, wide enough for two cars to pass each other in both directions. The roads eventually became longer and they pushed out in every direction.  

The American Road became better as the cars that drove along it improved their engineering. The highways had become an extension of the city. People began to demand comfort and luxury and their transportation now included tires and shock absorbers which took the roughness out of driving interiors, so roads had to be smooth.