Alligator or fatigue cracking is a series of interconnecting cracks caused by fatigue failure of the asphalt surface under repeated traffic load.
Cracking begins at the bottom of the asphalt surface (or sub-grade) where tensile stress and strain are highest under a wheel load. Alligator cracking occurs most commonly in areas subjected to repeated traffic loads, such as wheel paths. Alligator cracking is known as a high-severity structural distress. Typical alligator cracking sections are less than one foot on the longest side.
It is referred to as "alligator cracking" due to the similar looking texture that it shares with alligator's skin patterns.