DOS and saturation flow studies are critical for optimising traffic signal timing and enhancing overall traffic flow. The greatest number of cars that can pass through an intersection per hour under perfect conditions is referred to as saturation flow. It is measured in passenger car units (PCU) per hour and is affected by a variety of factors, including the number of lanes, lane width, and turning actions. DOS, on the other hand, is the length of time that vehicles experience at a signalised intersection, measured in seconds per vehicle. The number of vehicles on the road, the duration of the red signal phase, and the saturation flow are all factors that influence DOS.
Traffic counts are performed at a signalised intersection to measure the number of vehicles and their movements in order to undertake a saturation flow and DOS analysis. To capture traffic variations, counts are undertaken at various times of the day, on various days of the week, and during various seasons. The saturation flow and DOS values are derived based on the traffic counts. These values are then used to optimise traffic flow by optimising traffic signal timing.
Traffic signal timing optimization can help minimise congestion, increase travel time reliability, and improve the overall transportation experience for users. By minimising the amount of time vehicles spend idling at intersections, fuel consumption and emissions can be minimised, contributing to a more sustainable transportation system. Saturation flow and DOS studies are thus crucial for ensuring the optimal performance of signalised crossings and improving the overall mobility experience for customers.