[1] At the beginning of the 1950s, the American Association of State Highway Officials (AASHO) dealt with the question of how the size of the axle load affects the service life of a road pavement.
For this purpose, a test track was built in Ottawa, Illinois, which consisted of six loops, each with two lanes.
In the two-year test, trucks with different axle loads then drove the roads almost continuously.
The service life of the road is thereby reduced with approximately the fourth power of the axle load.
[2] This example illustrates how a car and a truck affect the surface of a road differently according to the fourth power law.