Quantifying the Economic Domain of Transportation Sustainability

The lens of sustainability refocuses the perception of transportation and allows a look beyond its accustomed role of providing vehicular mobility to the broader impacts of transportation on the environment, society, and the economy. As the understanding of transportation's function evolves beyond throughput and capacity, sustainability can be used as an organizing principle for transportation planning to promote livable communities. To fully understand and integrate the ideas of sustainability with transportation, the proper metrics and performance measures need to be developed and adopted. This study demonstrated how the theoretical concepts and definitions of transportation sustainability could be transformed into a practical metric for assessing the performance of the U.S. transportation system in terms of sustainability. The study focused on characterizing and measuring the economic aspect of sustainability in relation to transportation. The analysis was carried out for surface transportation at the statewide level and took into consideration the degree of urbanization of states. The final results described the relationship between urbanity, mode share, and the economic aspects of transportation sustainability. On the basis of this assessment, the best-performing states in terms of the economic aspects of transportation sustainability were more urban and had lower automobile mode shares.