In Corbett's time, the importance of the car was growing. More and more people were owning cars problems were increasing. Streets were over-crowded and people were experiencing traffic jams for the first time. Corbett theorized that transportation was the single largest problem facing the city. His vision of the healthy city was one with many levels, with different types of transportation on each level.
Transportation is a contentious issue in the natural environment as well as in the urban landscape.