Small, bowl-shaped depressions in the pavement surface that penetrate all the way through the HMA layer down to the base course. They generally have sharp edges and vertical sides near the top of the hole. Potholes are most likely to occur on roads with thin HMA surfaces (25 to 50 mm (1 to 2 inches)) and seldom occur on roads with 100 mm (4 inch) or deeper HMA surfaces (Roberts et al., 1996[1]).

Figure 1: Pothole as a result of fatigue cracking.

Figure 2: Fatigue cracking showing the beginning of a pothole.

Figure 3: Pothole on a residential road after heavy rains.


Roughness (serious vehicular damage can result from driving across potholes at higher speeds), moisture infiltration

Possible Causes

Generally, potholes are the end result of fatigue cracking. As alligator cracking becomes severe, the interconnected cracks create small chunks of pavement, which can be dislodged as vehicles drive over them. The remaining hole after the pavement chunk is dislodged is called a pothole.


In accordance with patching techniques.

Footnotes    (↵ returns to text)
  1. Hot Mix Asphalt Materials, Mixture Design, and Construction.  National Asphalt Paving Association Education Foundation.  Lanham, MD.