always form a washboard-like surface with ridges. The reason for this is that dirt roads have tiny irregularities; a wheel hitting a bump pushes it forward, making it bigger, while a wheel pushing over a bump pushes dirt into the next bump. However, the surface can remain flat for velocities less than 5 mph.

In many regions, dirt roads are commonly used as forest or rural access roads, where they are exposed to variable traffic loads and environmental conditions. Their performance is highly dependent on soil type, moisture content, and