| In recent years,the road traffic system has become increasingly developed,and the demand for transportation is also increasing gradually.There are various types of vehicles in the road system because people always choose different ways to meet their transportation needs.Large freight cars to meet freight demand and large public buses to meet passenger demand belong to large vehicles,private vehicles belong to small vehicles,and the bicycles suitable for short trips in cities belong to non-motor vehicles.Therefore,to further study the mixed traffic flow and lay a theoretical foundation for the future development of scientific and practical traffic control measures,it is necessary to understand the various characteristics of the vehicle and the driving habits of drivers,analyze the influence of different types of vehicles in traffic flow and the mechanism of interaction between them.Traffic flow modeling is a prevalent research method in the traffic flow research field.Based on the previous cellular automata traffic flow model,a new cellular automata traffic flow model is established by analyzing the characteristics of large and small vehicles on the road.By analyzing the simulation results of this new model,the interaction between different types of cars and the influence of vehicle characteristics on traffic flow are studied.This research has not only theoretical significance but also have practical application value.The main work contents of this paper are as follows:First of all,This paper draws out the purpose and significance of this study by analyzing the problems existing in the Chinese traffic system.Then this paper introduces the current research situation at home and abroad,points out the shortcomings in the present research,and explains the main research direction of this study.It expounds on the basic principle of cellular automata and traffic flow theory and reviews classical cellular automata traffic flow models.Secondly,a more practical traffic flow model will be build that considered different characteristics of vehicles,the different driving behavior of each type of vehicle,and the difference in acceleration and deceleration of different kinds of vehicles.It introduces the leading vehicle effect on the VDR model and,according to the speed difference between the vehicle and it’s leading vehicle,determines the deceleration amplitude of the current time step.Based on the above improvements,a new slow-to-start model,the LVE model,is established.The simulation results show that the free flow does not directly change to blocking flow when the road occupation rate reaches the critical value but gradually changes to blocking flow state after a transition period.Because the expected speed and safe distance has considered suppressing the formation of blocking,the simulation results of the space-temporal diagrams and thermal maps show a large number of stable small blocking groups in the road system.Finally,it adjusted the driver’s random slowing rule parameters when the driver stops for a long time by considering the driver’s psychology and behavior habits in the actual driving process.Considering the influence of synchronous distance on vehicle acceleration behavior,the difference of acceleration and deceleration performance of different types of vehicles,the SLVE model is established.By modifying the model parameters to simulate the proportion of other large vehicles,analyze the influence of the proportion of large vehicles on mixed traffic flow’s characteristic parameters.The simulation results show that increasing the proportion of large vehicles in the free flow area makes the flow rate decrease slightly.With the increase of the specific gravity,the critical value of the road occupation rate from the free flow to the blocking flow will also increase.Due to the low maximum speed and weak acceleration ability of large vehicles,the gap between vehicles and their leading vehicles in the road system has also changed.The stability of the road system has also improved.Figure 30 table 1 reference 67... |
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