Combined bottleneck effect of on-ramp and bus stop in a cellular automaton model
Song Yu-Kun(宋玉鲲) and Zhao Xiao-Mei(赵小梅)†
School of Traffic and Transportation, Beijing Jiaotong University, Beijing 100044, China; MOE Key Laboratory for Urban Transportation Complex Systems Theory and Technology, Beijing Jiaotong University, Beijing 100044, China
Abstract The combined bottleneck effect is investigated by modeling traffic systems with an on-ramp and a nearby bus stop in a two-lane cellular automaton model. Two cases, i.e. the bus stop locates in the downstream section of the on-ramp and the bus stop locates in the upstream section of the on-ramp, are considered separately. The upstream flux and downstream flux of the main road, as well as the on-ramp flux are analysed in detail, with respect to the entering probabilities and the distance between the on-ramp and the bus stop. It is found that the combination of the two bottlenecks causes the capacity to drop off, because the vehicles entering the main road from the on-ramp would interweave with the stopping (pulling-out) buses in the downstream (upstream) case. The traffic conflict in the former case is much heavier than that in the latter, causing the downstream main road to be utilized inefficiently. This suggests that the bus stop should be set in the upstream section of the on-ramp to enhance the capacity. The fluxes both on the main road and on the on-ramp vary with the distance between the two bottlenecks in both cases. However, the effects of distance disappear gradually at large distances. These findings might give some guidance to traffic optimization and management.
Received: 11 April 2009
Revised: 07 May 2009
Accepted manuscript online:
PACS:
45.70.Vn
(Granular models of complex systems; traffic flow)
Fund: Project supported by the National
Basic Research Program of China (Grant No 2006CB705500), and the
National Natural Science Foundation of China (Grant Nos 70631001,
70701004 and 70501004).
Cite this article:
Song Yu-Kun(宋玉鲲) and Zhao Xiao-Mei(赵小梅) Combined bottleneck effect of on-ramp and bus stop in a cellular automaton model 2009 Chin. Phys. B 18 5242
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