Toward the systematic diagnosis of freeway bottleneck activation

An active freeway bottleneck is a point characterized by the presence of queued traffic immediately upstream and unqueued (freely-flowing) traffic immediately downstream. It is shown that a freeway bottleneck´s activation can be diagnosed definitively using archived inductive loop detector data. Once the bottleneck´s location and time of activation were determined, potential signals of its activation were explored. It is shown that certain potential signals are evident immediately before upstream queue formation. As a result, it is suggested that these signals be used for systematic investigation of bottleneck behavior in either real time or in retrospect, on a more widespread basis.