Introduction
As auto travel and the economy recover from the COVID-19-related slowdown, transportation planners and engineers will need to decide how much new roadway capacity to build. In the post-World War II years, the U.S. built thousands of miles of highways—40,000 miles of Interstate highway alone between 1956 and 1980. However, the country has added significantly fewer miles over the past 40 years.
One reason that highway construction slowed is the growing challenge of building roadways, particularly in urban areas. Starting in the late 1960s, community groups began protesting the construction of Interstate highways, some of which divided neighborhoods. These protests led
