| In recent years, the traffic problems are becoming increasingly prominent. Especially, the traffic jams induced by road bottlenecks have become one of the most important factors to restrict urban development. Therefore, it is of great importance to establish traffic flow models to investigate macroscopic characteristics and jamming mechanism of the traffic flows, which will be helpful for improving planning, design and control of traffic system. The researches have important values on engineering application as well as practical significance. In this dissertation, based on the microscopic traffic flow models, several extended traffic flow dynamical models are proposed to investigate two-route traffic system, the motorized and non-motorized vehicle lanes with curb parking and highway maintenance by considering bottleneck effect, respectively. And the macroscopic dynamic characteristics of traffic flow are also explored via numerical simulation. Furthermore, we put forward some valuable suggestions for project implementation, design and management of curb parking.The main content of the dissertation are as follows.(1) Based on the Wahle’s two-route model, an improved cellular automaton model is established to simulate traffic flow by considering the speed feedback control strategy and multi-bottleneck effect, and the influences of symmetry, asymmetry and length of road bottleneck and other factors on traffic flow are investigated via numerical simulation. Furthermore, the formation mechanisms of traffic jams are also discussed in detail.The results show that the symmetric distributions of bottleneck position can optimize road resources and improve the utilization efficiency of road. When the bottlenecks are asymmetric distributions, the differences of the average density and velocity of system increase obviously with the increase of bottleneck gap, thus the utilization efficiency of two-route system decrease. Furthermore, the average velocity increase with the increase of the length of bottleneck, in this case that the road is better open. All these indicate that our research can provide a useful reference to improve the utilization efficiency of road, and set the reasonable location of the fixed bottlenecks (e.g., toll stations, etc.).(2) An extended cellular automaton traffic flow model is proposed to simulate traffic flow by considering the block interference of curb parking in the non-motorized vehicle lane, and the influences of with and without block interferences, the proportion of prepared parking vehicles, the number of parking strips and other factors on traffic flow are studied via numerical simulation. Moreover, the characteristics of typical space-time dynamics are also discussed in detail.The results show that at medium density, the average velocity and flow can be improved under without block interference. With the increasing of proportion of prepared parking vehicles, the average velocity and flow will usually decrease. However, when the parking strips are limited, the average velocity and flow are independent of the proportion of prepared parking vehicles. In addition, the multiple smaller parking strips are benefit to raise the average velocity and flow. These results provide the theory basis for project implementation, design and management of curb parking.(3) Based on the second research, an improved two-lane cellular automaton traffic flow model is established to simulation traffic flow by considering curb parking in the motorized vehicle lane, and the influences of with and without block interference, the proportion of prepared parking vehicles, the number of parking strips and other factors on traffic flow are studied via numerical simulation. Furthermore, the relation of the number of parking strips and the prepared parking vehicles is also discussed.The results show that the multiple small parking strips distributed in different positions are more useful than a large parking strip to improve road traffic capacity. Moreover, at the same conditions, the average velocity and flow are smaller than the previous study with curb parking in the non-motorized vehicle lane. All these indicate that the curb parking in non-motorized vehicle lane is better than that in motorized vehicle lane.(4) Based on NaSch model, an extended two-lane cellular automaton traffic flow model is constructed to simulate traffic flow by considering bottleneck effect induced by highway maintenance, and the influences of the limited velocity, length of slowdown section and other factors on traffic flow and traffic accident are investigated. Moreover, the position and style of traffic accidents are also explored.The simulation results show that in slowdown section, to design the appropriate limited velocity and length will reduce the occurrence of traffic accidents effectively. At medium density, it is found that the probability of traffic accidents to occur is the largest at the joint of traffic jam section and normal-velocity section. Furthermore, the lane-changing is the main reason to induce the occurrence of traffic accident, especially, when vehicles enter before the highway maintenance section, the probability of traffic accident is the highest. Therefore, to reduce the occurrence of traffic accident, the drivers should driver and change lane carefully in the highway maintenance section. In summary, the primary results can be useful for controlling and managing traffic flow, optimizing design of slowdown section and avoiding the occurrence of traffic accident. |
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