Exploring the Influence of the Congested Downstream on Traffic Flow at its Upstream Bottlenecks

With the rapid increase of private cars, urban road congestion is getting worse. As known, when the downstream section is free flow, the congestion for every bottleneck section starts from the bottleneck cell, and then gradually propagates towards its upstream. Many studies about bottlenecks are based on the assumption that the downstream of each bottleneck is free flow. In this paper, the authors investigated ramp systems with congested downstream. Based on the cell transmission model, a tri-cell ramp system with two bottlenecks is used as an example to explore what the convergence state of the bottleneck section is under the congested downstream section. Three cases are studied: free-flow downstream, middle-state downstream, and the most congested downstream, and the different convergence states. The results show that 1) if the downstream of the bottleneck is the most congested, the upstream bottleneck section converges to the most congested state no matter what the initial state is; 2) if the downstream is congested, the upstream section converges to congested states, and the degree of congestion in the upstream section increases; 3) the larger the density in the congested downstream, the more congested the final state of the ramp system.

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  • English

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  • Accession Number: 01532304
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jul 29 2014 1:55PM