Recent findings on simple attributes of freeway queue formation and propagation

Traffic observations at, and upstream of, some freeway bottlenecks are presented in three parts. The first two of these are of bottleneck activations: at a bottleneck formed by a diverge and at another by a merge, traffic features that gave rise to queueing are displayed. These were subtle and their identification relied upon processing the traffic data in special ways. But once diagnosed, the bottleneck causes proved to be uncomplicated and opportunities exist for mitigating them using simple traffic control strategies. Also presented (and likewise benefiting from special treatment of the data) are some observations of long queues upstream of a bottleneck. This third part of the presentation suggests that the spatial extents of freeway queueing, and the driver trip times between interchanges on queued freeways, can be modeled in simple ways.