Optimization of Traffic Signal Time and Coordination for Road Network with Oversaturated

Abstract

The increase in road user in terms of delay on peak hours in Vientiane Capital Lao PDR, intersections in Vientiane Capital demanded a traffic control scheme. Most road condition in Vientiane Capital City were 4 lanes 2 directions, 3.25m inner lane width and 2.75m outer lane (slow down lane) width that’s narrow. On the working day, the most of road user need to go ahead and made traffic jam finally. Existing of the traffic signal time and green phases were not matching within the traffic volume on each direction which it was shown in the cycle length in the intersections, such as some green phase was too sort, and other too long that’s made a queue. The cases of these problems were bad of traffic control and management system. The Webster Methodology in Traffic Engineering was presented to estimate traffic movement. A queuing system is used to generate the performance of traffic flow. And a Webster theory is applied to calculate the optimal length of each phase of the cycle. The aims of research including of the traffic volume at the intersection, optimization of traffic signal time, signal coordination and traffic management. The optimal cycle length was 100 second, and two-phasing permit better than one-phasing permit, and if improved the existing of traffic signal system and traffic management by linking of traffic signal each intersection to make the traffic condition will be better.