Cellular Automaton Traffic Flow Model And Its Application In Traffic Signal Timing

With the rapid increase in the per capita vehicle ownership in China,the problem of traffic congestion has increasingly restricted the economic development and the improvement of people's living standards.Therefore,improving or solving the traffic congestion problem has a strong practical significance,which also attracts many scholars to study it in depth and propose a series of theories and methods.Among them,the cellular automaton traffic flow model is one of the most famous methods.On the basis of fully summarizing and inheriting the original cellular automaton traffic flow model,this paper aims to establish a cellular automaton traffic flow model that fits the actual road traffic.Through the simulation of the model,we can understand some basic laws of traffic flow.The main research work of this paper is as follows:(1)For the shortcomings of the classic NaSch model and STCA model,based on the improvement of driving safety,the classic Gipps safety distance rule is introduced.The original vehicle travel rules and lane change rules were modified.Based on this,an improved two-lane mixed traffic flow model was established.With the viaduct as the simulation object,the model is simulated under the open boundary condition.Through the analysis of the features of space-time characteristics,output rate,mixing ratio and random slowing probability,It reveals the basic characteristics of the improved model and combs the basic laws of traffic flow.(2)Based on the improved two-lane mixed traffic flow model,the two-lane mixed traffic flow model considering the intention of entering the road is established.This paper improves the classic NaSch model and the two-lane STCA lane change model by considering drivers' intention to change lane under open boundary conditions.It presents a new two-lane mixed traffic flow model.It demonstrates that the average arrival rate ? is determined by the arrival rate ? and output rate ?,and is affected by the sensitivity parameter ?,and ? is not greater than ?.Vehicles' state on a road is determined by the output rate ? and is affected by ?.When a road is highly congested,the proposed model is capable of resulting in a higher throughput than the previously ones.(3)The ant colony labor division model is used to solve the dynamic and variable traffic signal timing problem.Based on the basic model,this paper proposes a new extended ant colony labor division model for traffic signal timing.This model is combined with the vehicle characteristics to modify the calculation method of environmental stimulus values.Using the vehicle delay in the unit period,the original fixed response threshold is modified to the dynamic response threshold,and the state transition equation is reconstructed.Based on the mixed traffic flow model of two-phase single-point intersection cellular automata,through comparative experiments and discussion and analysis,it is found that the extended ant colony labor division model can improve road traffic capacity and avoid local congestion according to road conditions and reasonable traffic signal timing.