the vast majority of road degredation isn't due to weather, its due to weight wear. As heavy vehicles travel down the road, they create a "ripple" on the road surface in front of the axle. You can create a similar effect if you run your hand across a loose sheet on top of your bed (you will see the wrinkle in the sheet in front if your hand). This bending is the method of road wear that causes like 99% of the maintenance need.