Dynamic Modeling, Numerical Simulation & Analysist Emoirical Data For Heterogeneous Vehicular Traffic

The traffic jam has been a more serious problem to the urban traffic system, so it isnecessary to study the property of the traffic system such as the formation of trafficjamming & its dispersal The urban traffic system is generally a two-dimensionalnetwork with mixing traffic flow, this paper is attempt to do some researchs on thetraffic flow by considering the mixed vehicles.Firstly, we study the local property of two-dimensional mixed traffic flow. By usingthe two-dimensional main-road model, we get its flow as a function of occupancy ratio.It is found that there is a flat region in fundamental diagram on which the flow ofmain-road do not change with the vehicles occupancy ratio, the flow only decrease whenthe mixed ratio of vehicles increase. By considering the influence of the nonsynchronoustraffic lights, we find that the whole flow hardly change with the traffic lightssynchronous or nonsynchronous, if the period of every traffic light is equal on these twosituations.Secondly, we study the global property of two-dimensional mixed traffic flow. Wepropose a two-dimensional traffic model with mixed vehicles via combining BML modelwith FI model. The averagy velocity as a function of vehicles occupancy ratio isobtained by computer simulation. The simulation shows that the critical occupancyratios on all conditions are far smaller than BML model, but well obey a power-law withthe mixed ratio. The typical configurations of the model on certain conditions mostlyappear new form. We also consider the influence of vehicles turning, and conclude thatlonger vehicles mainly determine the congestion of the mixed traffic flow.Finally, we measure the traffic of one crossroad on field in Naning, and analyze it numerically. By simulating it with the LWR model, we find the jam phenomena causeby different format in simulation. We do the stable analysis of different format that candrive vehicles away, and obtain that the flow Coupling relation in LWR model must meetsome new certain conditions. To make use of the new relation, the simlution indicatesthat it can well describe the relation between the flow and density at the initial stage, &is not the unrealistic case that the flow rapidly changes with the density. Compare to theempirical data, the numerical data is rather coincident, it can reflect the congest effectat high density, if also can reflect the disperseing process. Meanwhile, we verify that it isbetter to set these right-turning vehicles downstream of the intersection than they areset at the intersection, it can reduce the traffic congestion caused by the bottleneck.