Amir Abbas Rassafi - Associate Professor, Department of Civil Engineering, Imam Khomeini International University, Qazvin, Iran
Mahdi Ostadi Jafari - MSc. Grad, Department of Civil Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
Hassan Javanshir - Assistant Professor, Department of Industrial Engineering, Islamic Azad University, South Tehran Branch, Iran

Increasing pressures caused by negative consequences of transportation and traffic problems in major cities, have resulted many attempts towards improvement of planning and management of transportation systems, according to sustainability objectives. In this paper, a comprehensivemodel is developed using a system dynamics approach to evaluate sustainable urban transportation. This model includes social, economical, environmental, and urban transportation variables. Then, the validation of the model according to actual data for years 1994 to 2009 of City of Mashhadare performed. The base year for simulation was 2009 and the horizon year was 2044. This stage is very important because all of the analyses and decisions made in the following steps will be based on the calibrated model. The sensitivity analysis of the parameters of the model showed that the selected variables have considerable influences on urban transportation sustainability. The proposed model can be used to find the optimal strategy for sustainable urban transportation.

Sustainability, urban transportation, system dynamics, simulation