37 International Journal for Traffic and Transport Engineering, 2017, 7(1): 37 - 51 EVALUATION OF OPERATIONAL AND ENVIRONMENTAL PERFORMANCE OF MEDIAN U-TURN DESIGN USING MICRO- SIMULATION Ibrahim H. Hashim 1 , Mohamed Ragab 2 , Gaber M. Asar 3 1 Department of Civil Engineering, Faculty of Engineering, Menoufia University, Egypt 2 Department of Civil Engineering, Higher Institute of Engineering and Technology in Kafr El-Sheikh 3 Department of Mechanical Engineering, Faculty of Engineering, Menoufia University, Egypt Received 20 June 2016; accepted 23 August 2016 Abstract: Road intersections force vehicles to slow down and stop in varying patterns and contribute to the increase in vehicular emissions. The main aim of this paper is to evaluate the operational and environmental performance of median U-turn design. Also, it aims to compare this design with conventional three-leg and signalized three-leg intersections in terms of average delay, fuel consumption and air emissions including carbon monoxide (CO), nitrogen oxides (NO X ) and hydrocarbons (HC). The microscopic traffic simulation model VISSIM was used to model and analyze the three designs under a wide range of balanced and unbalanced flow conditions. The results indicated that, the median U-turn (MUT) design exhibited slightly lower delays than conventional three-leg intersection at balanced volume scenarios, up to approximately 1250 veh/hr/approach. After this volume level, the median U-turn (MUT) design exhibited higher delays than three-leg intersection. Also, the median U-turn (MUT) design exhibited lower air emissions and fuel consumption than other intersections at all balanced volume scenarios. In addition, under unbalanced volume scenarios, the average delay, air emissions and fuel consumption increased with the increase of main and/or cross street volumes for the median U-turn (MUT) design. Keywords: air emissions, median U-turn, three-leg intersection, traffic simulation. 2 Corresponding author: mohamedragab@sh-eng.menofia.edu.eg UDC: 502.3:504.3:621.43.086 DOI: http://dx.doi.org/10.7708/ijtte.2017.7(1).03 1. Introduction Road intersections play an important role in the overall performance of road network. They involve the highest traffic density, the longest vehicle idling time, and the most deceleration and acceleration rates. They are often “hot spots” of air pollution and have negative environmental and health impacts on vital buildings such as hospitals and schools in the vicinity (Lv, 2012). Thus, the demand for more efficient intersection designs is a high priority. There are different types of intersections, but the three-leg (T) intersection is the most common intersection design in Egypt. The median U-turn (MUT) is the most common unconventional intersection design in many countries today, as there are many advantages associated with the elimination of direct left-turns at intersections. For instance, it may improve the capacity of the intersection and reduce the number of