Experimental Results With Moving Bottlenecks

In this paper, the author present field observations and a new theory regarding moving bottlenecks on freeways. The observations focus on the occurrence of a steadily moving bottleneck on the I-880 freeway in Oakland, California, which was identified and characterized from loop detector data, including the behavior of the traffic stream around it. Oblique plots were used to reveal the location in time and space of the moving bottleneck's appearance including its trajectory over the freeway section. A set of controlled floating-vehicle experiments are described which involved the artificial introduction of moving bottlenecks into the traffic stream. The experiments revealed that the flow downstream of the bottleneck increases with the speed of the bottleneck when the bottleneck holds back a queue. This revelation results in a new theory which treats the moving bottleneck as a boundary condition which can be integrated with kinematic wave (KW) theory as well as with variants of this theory which account for multiple vehicle types and changes in driver psychology. The evidence leads that authors to conclude that the lengths of queues upstream of moving bottlenecks and the resulting vehicle delays are able to be predicted with reasonable accuracy.