Freeway traffic was observed over multiple days and was found to display certain regular features. Oscillations arose only in queues; they had periods of several minutes; and their amplitudes stabilized as they propagated upstream. The effects of the oscillations were not felt downstream of the bottleneck. Thus, their only effect on a queues growth was that its tail meandered over time by small amounts. Notably, the character of queued traffic at fixed locations did not change with time, despite the oscillations; i.e., traffic did not decay. There were changes over space, however. New oscillations formed in moderately dense queues near ramp interchanges and then grew to their full amplitudes while propagating upstream, even though the range of wave speeds was narrow. The formations of these new oscillations were strongly correlated with vehicle lane-changing maneuvers. But this pattern of formation and growth was less evident in a very dense queue (caused by an incident), although frequent lane changing occurred near the interchanges. (Author/publisher) For the covering entry of this conference, please see ITRD abstract No. E208120.
Samenvatting