Optimizing traffic flow at urban intersections and methods for reducing congestion
Abror Abduvalioyev Graduate (2026), Jizzakh Polytechnic Institute
Abstract
Intersections are the main bottlenecks of urban road networks, so improving how they operate is one of the fastest ways to reduce congestion. This article briefly explains why queues form at intersections and reviews the most practical measures for reducing them, from signal re-timing to demand management. It concludes that cheap operational measures should come first and costly systems should be used only where measurements justify them.
Keywords: traffic congestion, signalized intersections, signal timing, adaptive control, urban mobility
1. Introduction
Cities grow faster than their streets. Car ownership rises, but the road network inside the city can rarely be widened. Most delay does not occur on the open road but at intersections, where vehicles, buses, cyclists and pedestrians must take turns using the same space. A road link can carry far more vehicles than the intersection at its end can discharge, so the intersection decides how the whole corridor performs.
2. Why Congestion Forms at Intersections
At a signalized intersection each approach is served only during its green phase, so its capacity depends on the share of the cycle it receives. When demand approaches this capacity, delay grows very quickly and a small increase in traffic creates a long queue. The problem is made worse by lost time at every phase change, timing plans that no longer match current traffic, turning conflicts, parked or stopping vehicles that block lanes, and queues that spill back and block the neighboring intersection.
3. Methods for Reducing Congestion
Signal re-timing and coordination. The cheapest improvement is to recalculate the signal plan from current traffic counts and to use separate plans for the morning peak, midday and evening peak. On main roads, signals can be coordinated so that vehicles released from one intersection arrive at the next on green, which reduces stops, delay and fuel use.
Adaptive control. Detectors let controllers adjust green times to the vehicles actually present. Systems such as SCOOT and SCATS do this across whole networks. They are most useful where demand varies strongly, and they require reliable detection, communication and maintenance.
Geometric changes and roundabouts. Sometimes the layout is the real problem. Adding or lengthening turn lanes, moving parking away from stop lines or banning a conflicting turn at peak hours can raise capacity at low cost. At moderate and balanced traffic volumes, a roundabout can reduce delay and make crashes less severe.
Priority for people and demand management. Transit signal priority and safe pedestrian and cycle crossings move more people through the same space. Staggered working hours, parking policy and real-time traffic information reduce the number of vehicles that join the queue at the peak.
Intelligent transport systems. Video detection, radar and connected-vehicle data make it possible to measure traffic continuously and to improve the results of the measures above, but they should complement them and not replace them.
4. Conclusion
Most intersection congestion can be reduced without building new roads. A city should first measure its worst intersections, then re-time and coordinate signals, adjust the layout, and add adaptive control and demand management where they are justified, checking the results after each step.
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