English Abstract
Abstract :
A traffic signal is among the most important traffic control devices that are used to administer traffic flow efficiently, but it may cause congestion, if it is not well administered. Most traffic signals are controlled by either a fixed time signal or an actuated control system. Controlling an isolated traffic signal is easy especially when the demand on the intersection is below capacity, but it can be difficult when the intersection is part of a larger network. An adaptive control system is developed utilizing a fuzzy method to improve the traffic control system performance and to reduce the traffic average delay for four phases simple intersections within a grid network. Fuzzy method is a linguistic tool that can be applied to deal with complex traffic control problems providing an intelligent green time based on actual traffic flow data. The main functions of the developed control system are to accelerate the cycle time by shorting the cycle times and reducing the lost time by determining the green time for each phase based on the traffic flow. The control system was developed through four stages. The green time distribution models are designed at the first stage based on the intersection geometries. Second stage set of fuzzy rules are designed to determine the signal timing. Third stage, the system is initialized and finally, the system is executed. An Excel program and a Visual Basic language are used to design and run the developed control system. The developed control system was applied to five intersections in a simulated network in Kuwait during four different peak periods; 6:45 - 7:00, 14:15 - 14:30, 17:15 - 17:30, and 21:30 - 21:45 of Monday 11th Jan. 2016 by using the intersections geometries, average vehicle length and traffic flow from each phase. The results showed that the number of intersections’ cycles remained constant during the specified peak periods, while the number of vehicles passing the various phases through the network for each tested intersection increased by 7.3%, 22.1%, 5.3% and 12.7%, respectively. The total green time necessary to pass through these phases decreased by 1.0% and 4% for two periods, while it is increased by 3.6% and 0.1% for the other two periods. This indicated that the developed control system distributed the green time based on the traffic situation. The developed control system can be applied on a simple intersection with four perpendicular phases that may consist of any of the following roadway combination: collector road, major arterial and minor arterial roads.
