Which of the following best defines ruts in asphalt pavement?

Ruts in asphalt pavement are best defined as surface depressions that form due to the repetitive stress and deformation of the pavement material, often caused by the weight of vehicles. When heavy traffic travels over asphalt, the repeated compression can lead to permanent deformation, resulting in grooves or troughs along the wheel paths. These depressions can accumulate water and create hazards for drivers, as well as accelerate deterioration of the pavement surface.

The other options describe different types of pavement distress. Longitudinal cracks refer to cracks that extend parallel to the pavement's centerline and do not specifically indicate the presence of ruts. Alligator cracks, also known as fatigue cracks, appear as interconnected cracks that resemble alligator skin, indicating structural failure but not directly related to ruts. Potholes are localized depressions that occur when the asphalt surface fails, usually due to water infiltration and freeze-thaw cycles. While potholes can be a consequence of rutted surfaces, they are distinctly different in definition and appearance.