Sustainability and Operational Performance of Fixed-Time and Fully Traffic-Actuated Signal Control Across Different Intersection Types

Traffic signal-controlled intersections are important elements of urban transport systems, where inappropriate signal control strategies can increase traffic congestion, energy consumption, and pollutant emissions. Increasing and time-varying traffic intensity reduces the efficiency of traditional fixed-cycle traffic signal control; therefore, fully traffic-actuated control solutions are increasingly being applied. This study compares the efficiency of fixed-cycle and fully traffic-actuated signal control at eight traffic signal-controlled intersections in Bursa (Turkey), including four-way intersections and signalized three-way and four-way roundabouts with different geometric characteristics. The analysis was performed using a microsimulation method and PTV Vissim software, incorporating actual peak hour traffic flows, detailed intersection geometry, and camera-based vehicle detection logic implemented through the VisVAP module. Particular attention was given to the sustainability implications of signal control by jointly considering traffic performance, fuel consumption, and traffic-related pollutant emissions. The efficiency of intersections was assessed based on average vehicle delays, the number of stops, queue length, average speed, fuel consumption, and emissions (CO, NOx, and VOC). The results show that fully traffic-actuated traffic control usually improves both operational and environmental performance, but the magnitude of the effect depends on the intersection geometry and traffic flow distribution. At four-way intersections, average delays decreased by up to 47% and queue length by up to 67%, while fuel consumption and emissions decreased by around 20–39% in some cases. These findings indicate that fully traffic-actuated control can contribute to more sustainable urban mobility by reducing congestion-related inefficiencies, unnecessary fuel use, and local pollutant emissions, although the magnitude of these benefits depends strongly on intersection geometry and traffic flow characteristics.