An approach is generalized for enhancing a standard input-output diagram to represent graphically the time and distance that vehicles spend in a queue upstream of a bottleneck. The approach requires the construction of a curve depicting the cumulative number of vehicles to have reached the back of the queue as a function of time. The original technique, described in a previous paper, is reviewed for bottlenecks with constant capacity and for those where capacity changes once. The approach is then generalized to allow multiple changes in bottleneck capacity, and the original assumption of a triangular flow-density ( q-k) relation is relaxed to one that is piecewise-linear concave. Although it is consistent with the kinematic wave theory of traffic flow, the proposed approach is simpler to apply to complex problems because it avoids the laborious construction of a time-space diagram. It allows the estimation of several measures required in the evaluation of the impacts of bottlenecks, including the (accurate) number of vehicles in queue and the physical extents of queues at any time and the total time spent by vehicles in different traffic states.
Simple, Generalized Method for Analysis of Traffic Queue Upstream of a Bottleneck
Transportation Research Record
Transportation Research Record: Journal of the Transportation Research Board ; 1646 , 1 ; 132-140
1998-01-01
Article (Journal)
Electronic Resource
English
Simple, Generalized Method for Analysis of Traffic Queue Upstream of a Bottleneck
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