Delay Based Signal Control for an Isolated Intersection

Effective traffic management in urban areas is done by adapting traffic signal times to current traffic conditions. At isolated intersections this task is usually realised by fixed time or by conventional vehicle actuated signal controllers. The fixed time signals use predefined green times, they are reliable and cost-efficient but offer no opportunity to adapt on-line. Especially with rapidly changing demand patterns, the vehicle actuated controllers perform better because decisions whether to keep or to switch a phase are based on measurements of in-road equipment. However, being more flexible although means reduced availability if detection equipment gets out of order, leading to increased maintenance costs. Concluding, an improved signal control should combine high flexibility with sufficient reliability.