Why are the ruts in the same track so unevenly worn? (The left one varies in depth, shape, and size from the one on the right.) The difference could be due to the type of vehicle, the weight of the load, the frequency of use, and/or the terrain itself. Studies have shown that when Maltese limestone is wet, it loses 80% of its strength. So wherever storms have left standing water, the rock beneath the topsoil and vegetation weakens in that spot until the area dries. Erosion would occur unevenly, making some portions of the tracks deeper than others. And why so many tracks? Maybe when ruts got too deep and uneven, folks blazed a new trail.