CRITERIA FOR CHOOSING BETWEEN THE SIGNALIZED INTERSECTION AND U-TURN MOVEMENTS

Abstract

Traffic congestion at signalized intersections has been a recurring problem, especially at urban arterials during peak hours. Many signalized intersections are rapidly being converted into unconventional median U-turn intersections in Pakistan. The Unconventional Median U-turn (UMUT) is one of the popular alternatives used to mitigate congestion at signalized intersections. This research is an attempt to assess this low-cost "indirect right turn" technique. The performance of a 4 -legged signalized intersection and an unconventional median U-turn design have been compared by creating several scenarios based on different traffic demands, percentages of right-turn traffic, and median U-turn offsets. The signal timing of signalized intersections was optimized using the Synchro software, while the traffic simulation software VISSIM was used in the study to simulate the intersections. Python was used as a programming language via API COM interface to generate different scenarios of conventional and unconventional median U-turns in VISSIM. The evaluation parameters that were taken into consideration for the comparison of both types of intersections included average travel time delay, fuel consumption, and emissions. In MATLAB, vehicular delay equations and travel time models were developed for all movements in an UMUT design. These models were created based on simulation traffic data obtained from VISSIM. The approach utilized Generalized Linear Models (GLMs) with exponential relationships to accurately capture the associations between different input variables and output parameters. Internal validation procedures were carried out to ensure the reliability of the models.