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A pothole is a uniquely American phenomenon. Drive the highways of South Africa, Germany or France and you'll find few ruts and divots. Why potholes in America and not everywhere? The answer is the roadbed - the layer under the road.
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.
Now, in America, we spent millions fixing potholes, either shoveling asphalt in by hand, or slapping it in using expensive machines. And because some eighty percent of these patches are gone within a year we look for quick technological fixes.
For example, I read recently of a new material for patching potholes that is "harder and more dense" than concrete and will, of course, revolutionize road repair. But the key to fixing potholes is to prevent them. The secret is to spend time preparing the roadbed.
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.
Contrast this to France where the contractors must come up with their own specifications and must guarantee their work. This means that if a pothole develops the contractor has to fix it. But in the United States, once the job is done, as long as it has met specifications, the contractor is no longer liable. So, when a pothole appears, a whole new round of bids must begin. The prescription, then, for getting rid of potholes, is to give contractors adequate funds to build a strong roadbed, and in return require them to take responsibility for their road through out its lifetime.
Until this happens, though, our cars will take a beating every spring.
Copyright 2003 William S. Hammack Enterprises