Don't you have weather-induced damage there? Potholes that appear when the weather thaws in spring, or when rain and sun take turns wiggling the materials?
Weather-induced (largely water-induced) damage is driven largely by access to water provided by surface damage, which is driven by road weight and traffic volume similar to deeper damage, but also by traffic speed and resulting tire hydraulic action more than deeper damage is. Low-speed, low-traffic-volume roads than generally see personal passenger vehicles and smaller delivery vehicles without many heavy trucks will also see a lot less weather damage.