To make a road, engineers first prepare the soil: They mix it and smooth it and then compact layers of rock on top. Next they make a mixture of rocks stuck together by asphalt. Asphalt is the gooey stuff left over from distilling crude petroleum. This rock and asphalt conglomerate is dumped onto the roadbed where a paving machine spreads it to finish the road. And then, in America, potholes form. Small cracks in the pavement fill with water, which freezes and expands the cracks. The ice melts in the spring leaving a gap and weakening the pavement, which eventually gives way, creating a pothole. In South Africa, which has perhaps the world's best roads, they do lots of compacting, smoothing, and mixing of the underlying soil to create an even layer. This gives the road a good foundation so that when cracks do appear, they don't easily form potholes because the well-packed ground doesn't give way. This careful approach is used in most of Europe, so why not here? Well, a pothole is not just a technological thing, it's also a political entity. Usually we think of European nations as steeped in governmental regulation, and of the United States as a free market, but actually the opposite occurs in building roads. In the United States the government sets specifications and asks contractors to meet them. Once done with the road they have no more responsibility.