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.