Modeling of Delay Induced by Downstream Traffic Disturbances at Signalized Intersections

Macroscopic models that can be used to estimate the delay at signalized intersections caused by downstream traffic disturbances, such as queues in closely spaced settings, are presented. The models use basic traffic flow properties and control parameters at neighboring intersections. The models are applied to a hypothetical two-signal system. The results show that the delay caused by downstream disturbances can be significant and therefore must be included in level-of-service and capacity analyses. The results also show that control parameters, such as offsets and green splits at upstream and downstream approaches, play key roles in reducing delay. Validation by the use of microscopic traffic simulation shows close agreement between the delay estimates from the proposed models and that from the microscopic simulation model.