دراسة محاكاة حركة المرور لتغيير دوار إلى تقاطع ذو إشارة ضوئية

A Traffic Simulation Study for Changing Roundabout into Signalized Intersections

abstract

Karbala governorate is regarded as one of the most well-known governorates in Iraq for its religious and tourist attractions, which polarized many visitors, resulting in a growing need for transportation system services. As a result, congestion is common in many streets and intersections. In particular, at the roundabouts that are suffering from significant congestion. This research aims to study traffic operations due to various performance measures at the roundabout. Furthermore, study the roundabout after change it to signalized roundabouts and signalized intersections. Then, traffic growth after five years is studied due to those measures.
The research unit is focus on three high-traffic roundabouts in the center of Karbala district (CKD) (Al-Tarbia, Said Al-Assar, and
Al-Mohafada). A video recording is obtained from the Karbala Police Department, through which the traffic volumes required in the study are calculated during (7:30AM-8:30AM), (12:30-13:30), and (19:30-20:30) during peak hours. The Planung Transport Verkehr Vissim 2022 program is relied upon to create a model that simulates reality.
The results showed a significant delay in the studied roundabouts, with a level of service F for all roundabouts. Due to converting the roundabout to a signalized roundabout and a signalized intersection, the level of service LOS shifted ( from F to D and C ) and (from F to E and D ), when the average delay decreased at signalized roundabouts by 40% and decreased by 66% at signalized intersections, and the average queue length decreased by 16% and 27% respectively.
The results of the effect of traffic volumes on the performance of the roundabout and comparing the three cases that have been studied (roundabout, signalized roundabout, and signalized intersections) indicate that traffic arrival rates of 0.2 v/s/l are achieved, after which it is preferable to convert the roundabouts to a signalized roundabout. Moreover, it is preferable to convert the roundabout to signalized intersections at 0.29 v/s/l.
The study of the effect of the growth rate of traffic volumes showed that most signalized intersections would return to the level of service F in a few years that do not exceed five years. Changing roundabout into signalized roundabout and signalized intersection shows an apparent effect on the environmental parameters CO, NOx, VOC, and fuel consumption, as all factors decreased in different proportions.