Localized pavement surface areas with slightly lower elevations than the surrounding pavement. Depressions are very noticeable after a rain when they fill with water.

Depression in a parking lot.
Figure 1: Depression in a parking lot.

Depression in a parking lot.
Figure 2: Depression in a parking lot.


Roughness, depressions filled with substantial water can cause vehicle hydroplaning

Possible Causes

Frost heave or subgrade settlement resulting from inadequate compaction during construction.


By definition, depressions are small localized areas. A pavement depression should be investigated to determine the root cause of failure (i.e., subgrade settlement or frost heave). Depressions should be repaired by removing the affected pavement then digging out and replacing the area of poor subgrade. Patch over the repaired subgrade.