Evaluating Three Alternative Designs for Reducing Delay at an Intersection in Dohuk, Iraq

ABSTRACT: Traffic delay is one of the most important factors used in intersection analysis. This study focused on the average delay by looking at different alternative junction models. These different models analyzed with and without signalization according to cycle length in order to help create alternate designs. Green intervals were optimized to reduce average delay in order to assist the level of service for the given junction. The traffic and geometric data were taken from the Imam Hamza Intersection as a case study. A delay problem in this intersection of Dohuk city (northern Iraq) was analyzed and redesigned under the present conditions of right-of-way and volumes of traffic. Firstly redesign for signalized intersection was done by expanding the roads of each approach. Then designs of three new interchange models were proposed. A forecasting of traffic volumes for the next fifteen years was taken using each design model. The simulations for these new models were taken by applying different scenarios for each model in order to find the best results of delay and level of service. Likewise a comparison was made based on the best amount of delay obtained from these new models. Finally, the level of delay for the peak hours of each model was compared with the current level of delay in the intersection in order to find the total delay hours for next fifteen years and determine the most effective design in terms of reducing delay in the given intersection. The conclusion of this study displayed the second model diamond interchange had the minimum results of delay comparing with the other models. Keywords: Delay, Signalized intersection, Diamond interchange, Imam Hamza Intersection, Level of service, Traffic jam, Delay time cost. …………………………………………………………………………………………………………………………