Route Choice Strategies In Cellular Automaton Models For Traffic Flow In Urban Road Networks

The traffic flow on urban road network is a hot issue in traffic science.The reasonable route choice of each driver based on the traffic information can help alleviate traffic congestion and improve the performance of road network.In this paper,cellular automata models are used to study the dynamic evolution process of traffic flow in urban road network.More attention is paid on the route choice strategies adopted by drivers which are determined by road traffic information and their influence on the critical density.The main contribution of this paper is as follows:1.Drivers’ route choice strategies in the BML-like modelsBased on the BML model with permission of lane-changing,a set of rules for changing lane are proposed which consider the congestion information from both the current lane and the target lane as well as the influence of the turn signal.Through numerical simulation,it is found that compared with the BML model without traffic lights,this lane-changing mechanism can improve the traffic operation of the system.Compared with the BML model with traffic lights,this lane-changing mechanism cannot improve the critical density of the system,but can make the system reach its steady state faster.2.Drivers’ route choice strategies in the Manhattan-like networkA Manhattan-like 2-lane two-way road network is established and OD pairs are randomly assigned to every vehicle.The route choice strategies are investigated in detail.The author proposes two strategies :(1)considering both the road section density and the travel time of the vehicle just passing through the road section,a route choice strategy based on combined local information is proposed;(2)a route choice strategy based on global information(reflecting the level of road congestion)is first proposed by the author which borrows the ideas from the concept of ‘floor field’ in pedestrian flow.Numerical simulations show that compared with the single local information strategy,the combined local information strategy can improve traffic operation.Compared with the combined local information strategy,the global information strategy can effectively improve the capacity of road traffic network.In addition,based on the global information strategy,the performance of road traffic network with and without traffic lights is investigated.It is shown that under the guidance strategy of global information,the road network without traffic lights has larger critical density and traffic flux.3.Application of combined local information strategy on 4-lane dual carriageway regular road networkBased on the 4-lane dual carriageway road network which can reflect the main characteristics in real traffic,this paper investigates the underlying mechanism of traffic flow when drivers adopt the combined local information strategy to find the way.In addition,the influence of the structural parameters of the road network and the setting of traffic lights on the capacity of the road network is also studied.It is found that too many intersections and too long section will reduce the critical density of the system.