According to recent estimates, 85% of U.S. consumption of asphalt (as asphalt concrete) is used for the paving of roads (1). My first memories of asphalt coincide with an early appreciation of geologic time, which occurred during visits to the La Brea Tar Pits in Los Angeles in the early 1960’s. Like city streets softening and beginning to melt in summer heat, palpable were the sticky tar deaths of pre-historic creatures.