To determinate the expressway capacity near a bus bay stop with an access, capacity models on the expressway near a bus stop with an access were developed on the basis of gap acceptance theory and queuing theory. Depe...To determinate the expressway capacity near a bus bay stop with an access, capacity models on the expressway near a bus stop with an access were developed on the basis of gap acceptance theory and queuing theory. Depending on a bus stop position to an entrance or an exit ramp, the capacity models were developed for four cases. Bus bay stops with overflow and bus bay stops without overflow were considered. A comparison of simulation experiment and model calculation was carried out. Results show that the suggested models have high accuracy and reliability, at bus arrival rate below 60 vehicles per hour(veh/h) or vehicle volumes at the entrance and the exit below 200 passenger cars units per hour(pcu/h), and there are no significant difference in the capacities for four cases. When bus arrival rate is above 240 veh/h, the capacities of all four cases will decline rapidly. With berth number increasing, the increasing of the capacities is no obvious for four cases. As the bus arrival rate and vehicle volumes at the entrance and the exit increase, bus stops located downstream of an entrance and upstream of an exit have a remarkably effect on the capacities. The latter case is much heavier than the former. Those results can be used to traffic design and optimization on urban expressway near a bus stop with an access.展开更多
The class of bi-directional optimal velocity models can describe the bi-directional looking effect that usually exists in the reality and is even enhanced with the development of the connected vehicle technologies. It...The class of bi-directional optimal velocity models can describe the bi-directional looking effect that usually exists in the reality and is even enhanced with the development of the connected vehicle technologies. Its combined string stability condition can be obtained through the method of the ring-road based string stability analysis. However, the partial string stability about traffic fluctuation propagated backward or forward was neglected, which will be analyzed in detail in this work by the method of transfer function and its H∞ norm from the viewpoint of control theory. Then, through comparing the conditions of combined and partial string stabilities, their relationships can make traffic flow be divided into three distinguishable regions, displaying various combined and partial string stability performance. Finally, the numerical experiments verify the theoretical results and find that the final displaying string stability or instability performance results from the accumulated and offset effects of traffic fluctuations propagated from different directions.展开更多
基金Project(2012CB723303)supported by National Basic Research Program of China
文摘To determinate the expressway capacity near a bus bay stop with an access, capacity models on the expressway near a bus stop with an access were developed on the basis of gap acceptance theory and queuing theory. Depending on a bus stop position to an entrance or an exit ramp, the capacity models were developed for four cases. Bus bay stops with overflow and bus bay stops without overflow were considered. A comparison of simulation experiment and model calculation was carried out. Results show that the suggested models have high accuracy and reliability, at bus arrival rate below 60 vehicles per hour(veh/h) or vehicle volumes at the entrance and the exit below 200 passenger cars units per hour(pcu/h), and there are no significant difference in the capacities for four cases. When bus arrival rate is above 240 veh/h, the capacities of all four cases will decline rapidly. With berth number increasing, the increasing of the capacities is no obvious for four cases. As the bus arrival rate and vehicle volumes at the entrance and the exit increase, bus stops located downstream of an entrance and upstream of an exit have a remarkably effect on the capacities. The latter case is much heavier than the former. Those results can be used to traffic design and optimization on urban expressway near a bus stop with an access.
基金Projects(51108465,71371192)supported by the National Natural Science Foundation of ChinaProject(2014M552165)supported by China Postdoctoral Science FoundationProject(20113187851460)supported by Technology Project of the Ministry of Transport of China
文摘The class of bi-directional optimal velocity models can describe the bi-directional looking effect that usually exists in the reality and is even enhanced with the development of the connected vehicle technologies. Its combined string stability condition can be obtained through the method of the ring-road based string stability analysis. However, the partial string stability about traffic fluctuation propagated backward or forward was neglected, which will be analyzed in detail in this work by the method of transfer function and its H∞ norm from the viewpoint of control theory. Then, through comparing the conditions of combined and partial string stabilities, their relationships can make traffic flow be divided into three distinguishable regions, displaying various combined and partial string stability performance. Finally, the numerical experiments verify the theoretical results and find that the final displaying string stability or instability performance results from the accumulated and offset effects of traffic fluctuations propagated from different directions.
