An indicator-based algorithm to measure transportation sustainability: A case study of the U.S. states

Nowadays, there is a growing interest in applying the concept of sustainable transportation around the world. However, measuring the level of sustainability of transportation for a particular territory is an issue which is not well addressed due to several numbers of various indicators. Sustainable transportation encompasses environmental, social and economical dimensions which each dimension is composed of various subdivisions. To comprehensively address all sustainability dimensions and their subdivisions, several indicators are required. The aim of this paper is proposing an algorithm as a framework to take into account various number of indicators in different dimensions and subdivisions of transportation sustainability. The method of Principal Component Analysis/Factor Analysis (PCA/FA) was used to overcome the limitations of other methods used in previous studies. The proposed algorithm composes composite indices in each of transportation sustainability dimensions as well as their subdivisions and develops the transportation sustainability index (ITS) to measure the sustainability of transportation. To put the algorithm into practice, 89 sustainable transportation indicators are used based on available data. As a case study, transportation sustainability indices were determined for 50 states and the Federal District of Columbia in the U.S. according to the proposed algorithm. Thereby, the relative sustainability of transportation among the U.S. states is demonstrated. Results showed while the District of Columbia, New York and Massachusetts were the most sustainable, Mississippi, Wyoming and North Dakota were the least sustainable states.