VOLUME 2, 2019 ISSN: 2617-9946 DOI: 10.31058/j.ud.2019.21001 Submitted to Urban Design, page 1-13 www.itspoa.com/journal/ud Investigating the Effects of Fuel Price on Inter-City Transportation Utilizing System Dynamics Approach and Simulation (Case Study: Inter-City Transport, Iran) Mohammad Reza Nasiri Jan Agha 1 , Morteza Bazrafshan 1 , Abbas Mahmoudabadi 2* 1 Islamic Azad University, Lahijan Branch, Guilan, Iran 2 Industrial Engineering Department, Mehrastan University, Guilan, Iran Email Address moh_nasiri70@yahoo.com (Mohammad Reza Nasiri Jan Agha), bazrafshan@liau.ac.ir (Morteza Bazrafshan), mahmoudabadi@mehrastan.ac.ir (Abbas Mahmoudabadi) *Correspondence: mahmoudabadi@mehrastan.ac.ir Received: 27 February 2019; Accepted: 30 March 2019; Published: 28 April 2019 Abstract: Transportation system is known as a complex system composed of multiple variables and linear/non-linear feedback loops influenced by economic, geographical, social and environmental factors. Transport modeling is commonly proposed to evaluate and simulate the performance of system with or without inter-relations on transport system. In the present research work, system dynamics approach is utilized for modeling and simulating the intercity transportation in order to access the effects of fuel price on intercity roads traffic volume. The proposed model consists of internal interactions and relations on intercity transport system as well as simulation for validation. Sensitivity analysis has been done based on four scenarios on various fuel price increment rates of 5%, 15%, 20% and 25% in three different periods of five, ten and twenty years, known respectively as short, medium and long term periods. Simulation results revealed that during the above mentioned periods, commercial traffic on intercity roads are linearly grown up while the increasing rates of fuel prices has remarkable impacts on daily traveled vehicles over the intercity roads. Therefore, national authorities who are dealing with setting fuel prices should notice that policies on fuel prices have smooth impacts on intercity road traffic and should be carefully studied and investigated before taking decision. Keywords: Fuel Prices, Traffic Volume, Transportation, System Dynamic, Commercial Vehicles 1. Introduction 1.1. Transportation and Emission Road transport system is a complex system involving multiple variables and non- linear feedback loops which are influenced by many attributes such as transport