Research On Traffic Dynamical Characteristics And Nonlinear Density Waves With Consideration Of Navigation

In this dissertation, based on the existing macroscopic and microscopic models for traffic flow, several improved mathematical models in accordance with the rapid development of Intelligent Transportation System (ITS) are proposed, and the corresponding theoretical analysis and numerical simulation are performed. In addition, the relationships between macroscopic and microscopic traffic models are examined, in which emphasis is particularly laid on the investigation of the various nonlinear density waves in traffic flows. The contents of the dissertation are as follows.Ⅰ. A novel concept about the variable security gap and effective gap are introduced into the original NaSch cellular automata model, resulting in several improved CA models.With the consideration of the influence of leading car on the following one, the effective gap is introduced into the original NaSch cellular automaton model, and a novel concept about the variable security gap is proposed. The security gap was regard as a minimum constant in previous work, while we claim that it is variable according to the velocity of the studied car, that is, a faster car needs longer security distance to its leading car compared with a slower one. Through simulation we determined the proportional constant in the relation between the variable security gap and the velocity of studied car, named as speed adjusting coefficient for security gap, which should be taken as T = 0.5. In this way, a new model—variable security gap NaSch model is established. With the aid of the model, we studied further the effect and differences brought about by the different orders of the randomization step in the evolution rule, and put forward a new cellular automaton model—variable security gap sensitive driving model. The simulation results indicate that the maximum flow deduced by the above modified models are larger than that by the NaSch model and moreover the maximum flow of the latter is in better agreement with the observed data. A novel cellular automaton model for traffic flow on highway is thus proposed by considering Intelligent Transportation System (ITS), called the cooperative driving cellular automaton model. It includes some factors related to real traffic such as the effective...