Development & Application of the Transportation Index for Sustainable Places (TISP)

The purpose of transportation systems go beyond the movement of people and goods. These systems shape the natural and built environment which subsequently affects social and economic interactions. However, conventional metrics typically only address the mobility aspect of transportation via measures such as level of service and congestion. Metrics are needed to evaluate the broader impacts of transportation. This work describes the Transportation Index for Sustainable Places (TISP), a performance metric designed to assess the sustainability of transportation systems with respect to environmental, social, and economic outcomes. The development of the TISP was guided through literature review focused on understanding existing performance measures and the numerous conceptualizations of sustainability. From this review, we developed a definition of transportation sustainability and translated it into a model to be used as our framework. The results of this work show that statewide transportation systems have significant differences with respect to environmental, social, and economic sustainability issues. These differences are in a large part due to the types of transportation systems among the states. States that are more dependent on automobile travel tended to have poorer sustainable outcomes. Conversely, states offering more diverse travel options tended to be more sustainable when rated with the TISP