While browsing through the alt.folklore.urban usenet group, I noticed a debate raging over the question of how deep American roads are. Apparently (so the urban legend goes) American roads can only be built to a fairly shallow depth in order to make the land under them more easily reclaimed for farming. By contrast, European roads are built to a much deeper depth. As a consequence, European roads are much more durable than American roads and need fewer repairs. The usenet group didn't appear to have reached any conclusion about the validity of this claim, but I can't imagine it's true. I think the frequency of road repairs is mainly a function of weather conditions (does the ground freeze and thaw a lot) and the amount of traffic on the road. I can't find any references on Google to American laws stating that roads have to be kept shallow for the benefit of future farmers.