Evaluation of sustainable policy in urban transportation using system dynamics and world cities data: A case study in Isfahan

Study of transportation infrastructure of various cities and its environmental, economic and social impacts could shed some light on identifying successful policies for sustainable transportation. Few studies have addressed sustainability covering various cities of the world. The aim of current study was to analyze impacts of various transportation policies using system dynamics model based on pertinent data of world cities. The study database was developed based on few comprehensive databases covering numerous cities over 4 decades. Based on the study database, 9 urban sustainable transportation indicators were selected, 3 indicators presenting each key group of environmental, economic and social sustainability. Furthermore, a composite index was applied for combining the selected indicators. In order to analyze transportation sustainability in historic city of Isfahan, a system dynamics model was developed. Urban transportation causal loops were conceptualized and the dynamic relations among urban transportation variables were created to develop the pertinent urban dynamics model. Trip generation, modal share, transportation supply and equilibrium between supply and demand were the key modules of the developed model. Moreover, economic, social and environmental indicators were the key outputs of the model. The model inputs were urban characteristics pertinent to transportation. To validate the results, time-series data were used and model estimation was satisfactory. By monitoring Isfahan sustainable transportation indicators using future scenarios, efficacious transportation policies were identified. The model results reflected that transit network development is the most important policy for Isfahan sustainability. (C) 2014 Elsevier Ltd. All rights reserved.