Macroscopic Traffic Flow Model Considering The Throttle Dynamics

With the development of economy and society,the living standards of people are gradually improved while the pace of the lifes becomes more rapidly,such that people pay more and more attention to the time cost,in particular,the traffic trip time cost is a very important part of it.Traffic system is an important carrier to realize traffic operation,with the increase of car ownership,the demands for transportation system become higher.The traffic system is intricate,nowadays,once the traffic flow in one road of the traffic system is not smooth,which will directly or indirectly lead to more roads with slow driving or traffic congestion and result that the cost of traffic trip time increases dramatically.In addition,the vehicles in congested traffic flow would start and stop frequently,which will undoubtedly increase the emission of tail gas,environmental pollution,noise pollution and other problems.Although many countries have made great efforts to improve the transportation system,the traffic congestion has always been an important problem in the traffic field.The traffic congestion reflects the shortage of traffic sources in the traffic system during a specific period of time.In the field of macroscopic traffic flow theory,the density of traffic flow is usually used to describe the evolution behavior of traffic flow and the flow of traffic indicates the vehicular traffic rate.When traffic jam is occured,the density in congested area increases sharply and the flow of traffic decreases.Therefore,the evolution characteristics of traffic flow can be analyzed by studying macroscopic traffic flow model.Nowadays,regarding macroscopic traffic flow model,most of studies mainly consider the effects of the states of vehicles and road structure information and other factors,however,in the real traffic system,vehicle dynamics information is also an important factor affecting the traffic system.Therefore,the macroscopic traffic flow modeling research considering the effects of the throttle dynamic information is a supplement and improvement to the current traffic flow theory research.This thesis focuses on the macroscopic traffic flow modeling in traffic system.On the one hand,a macroscopic traffic flow model considering throttle dynamics information is proposed,the effectiveness of the macroscopic model is analyzed by using characteristic linear method,shock wave theory and negative velocity theory.On the other hand,the stability of the model is analyzed by using the small perturbation method.The stability condition range and the ability of eliminating external disturbance of the proposed model are compared and analyzed by numerical simulation experiments.Eventually,the effectiveness of the proposed macroscopic model is further verified.The contributions of this thesis include the following two aspects:1.A macroscopic traffic flow model is proposed by considering throttle dynamics information,and the characteristics of the model are also analyzed.In this thesis,a macroscopic traffic flow model is proposed by considering throttle dynamics information to improve the smoothness and stability of traffic flow.Firstly,full velocity difference(FVD)macroscopic model and throttle-based full velocity difference(T-FVD)microscopic model are comprehensively analyzed in the traffic flow modeling.In the field of microscopic traffic flow,the cognitive of traditional traffic based on vehicle status information is extended to that based on vehicle status information and throttle dynamics information.Secondly,the negative velocity analysis,characteristic velocity analysis and shock wave condition analysis of the new model are carried out.The results show that the new macroscopic traffic flow model conforms to the basic principle of traffic flow anisotropy.There will be no negative velocity phenomenon in the proposed model which implies that no vehicle backwards phenomenon occurred in traffic flow.Meanwhile,the model can effectively smooth the sudden shock wave under certain conditions,which further verifies the effectiveness of the proposed model.2.The stability of the proposed model is analyzed,comparing the stable condition range and the ability of external disturbance rejection of the proposed model and FVD model through numerical simulation.Regarding the macroscopic traffic model,firstly,the stability of the proposed model is analyzed by using the small perturbation method.Secondly,the proposed model is compared with FVD macroscopic model which doesn't consider the throttle dynamics information:(1)The range of stability conditions of the proposed model are compared and analyzed;(2)The stability and the ability of external disturbance rejection of the macroscopic model are compared and analyzed by observing the amplitude and frequency of disturbance in density wave.The results show that the stability and the ability of external disturbances rejection of the proposed model are better than those of the FVD macroscopic model,which further verifies the effectiveness of the proposed model.