Evaluation of Selected Roundabout in Al-Diwaniyah City by using Vissim

Abstract

Traffic simulation models considered as one of the most important tools that are widely used to analyze complicated traffic sections and suggesting alternatives solutions prior to applying in site. Traffic congestion usually starts at intersections and propagate upstream and caused longer travel time, delay at intersection (low level of service) and bad environmental areas. As in the other cities, Al-Diwaniyah city has many intersections that created such problems. This work considers traffic microsimulation (Vissim program) which is traffic simulation program to simulate traffic at selected congested intersections at Al-Diwaniyah city, Iraq. Real traffic data were collected from a selected sites representing a roundabout intersection. Manual method were used to collect data at a day Sunday at peak hour 7 am-8 am for each approach on intersection for periods reaching to a month. The first step was using the Vissim program to simulate and evaluate the level of service of selected roundabout which is eagle roundabout. The second step give solution to enhance the traffic flow and reduce the queue length on this site which is replace the roundabout by signalized intersection and use the Vissim program to simulate this condition.