Roads are by no means public goods, as it is very possible to exclude people from them, e.g. tolls. A good example is a dam. If you live in a valley that floo

Roads are by no means public goods, as it is very possible to exclude people from them, e.g. tolls. A good example is a dam. If you live in a valley that floods every year, the government may well come in and say, "we're going to build a dam." But by its very nature, you cannot exclude people from this -- the dam will hold back all of the water, not just for some of the people in the valley.