13

One of the most important factors in building a road is drainage. If every other aspect of highway

design and construction is done perfectly but the drainage does not work well, the road will fail quickly.

Figure 13.1 is a picture of a road less than a year old that did not have adequate drainage in the fill upon

which the pavement structure was built. Even when the failure is not catastrophic, water in the highway

structure will inevitably lead to premature failure. They are called “high ways” because early road builders

knew it was necessary to construct roads above the ground and away from water.