Yao-Ming Yuan

Totally asymmetric exclusion processes on two intersected lattices with open and periodic boundaries

In this paper, we study TASEPs on two intersected lattices. One TASEP has an open boundary (lattice 1) and the other has a periodic boundary (lattice 2). Extensive Monte Carlo simulations are carried out. It is found that the system phase diagram structure depends on the density ρ on lattice 2. Three critical densities ρc = 1/3, 1/2 and 2/3 are identified and four phase diagram structures are observed. The density profiles corresponding to all stationary phases and the phase boundaries are calculated using mean-field analysis. The analytic results are in good agreement with the simulation results.

TRAFFIC BEHAVIOR IN A TWO-LANE SYSTEM CONSISTING OF A MIXTURE OF BUSES AND CARS

In this paper, a two-lane traffic system consisting of a mixture of buses and cars is studied. The buses stop at each bus stop to pick up passengers and are not allowed to change lane. The cars may change lane when hindered by preceding vehicles. Our simulations show that with a fixed number of buses, four states of the traffic system are identified. The spatial-temporal plots of the four traffic states, and the trajectories of buses at different densities are presented. A gradual transition instead of sharp phase transition from bunching state to homogeneous state of the buses is found. Next, we study the system behavior at different number of bus stops, and an optimal number of stops is suggested. Finally, the influence of bus stops on the fundamental diagram is studied.

Asymmetric coupling in multi-channel simple exclusion processes

In this paper, we investigate N-channel simple exclusion processes in which particles can move across N parallel lattices and jump fully asymmetrically between the channels. Monte Carlo simulations are carried out to investigate the phase diagrams and density profiles of the system. It is shown that the phase diagram structure changes with increase of N. Moreover, how the phase diagram depends on N is obtained. A vertical cluster mean-field analysis is carried out; it shows good agreement with simulations.

Totally asymmetric simple exclusion process with a shortcut

In this paper, we study the interplay of a totally asymmetric simple exclusion process (TASEP) with a shortcut in its bulk under open boundary conditions. Two different models are introduced: (i) model A for molecular motor motion, and (ii) model B for vehicular traffic. The phase diagrams and density profiles of both models are studied. It is found that although the phase diagrams of both models can be classified into three regions, the phases corresponding to these regions and the phase boundaries between these regions are quite different in these two models. Moreover, the approximate stationary-state solutions of model A have been carried out and it is shown that the analytical results are in good agreement with the results of Monte Carlo simulations.

Spontaneous symmetry breaking in totally asymmetric simple exclusion processes on two intersected lattices

This paper studies totally asymmetric simple exclusion processes (TASEPs) on two intersected lattices. Three different models are introduced: model A for molecular motor motion, and models B and C for vehicle traffic. Extensive Monte Carlo simulations are carried out. Phase diagrams and density profiles of the three models are investigated. It is shown that phase diagrams of all the three models are divided into three regions. The phase boundaries are calculated by an approximate mean-field approach. It is found that the analytic solutions are in good agreement with the results of Monte Carlo simulations. For models B and C, spontaneous symmetry breaking is identified. The particle density histograms and qualitative domain-wall explanation are presented to describe the spontaneous symmetry breaking phenomenon. Finally, in model C, the effect of lane-changing probability p on spontaneous symmetry breaking is investigated. A threshold of p for the occurrence of symmetry breaking is obtained.

SYNCHRONIZED FLOW AND PHASE SEPARATION IN A TWO-LANE CELLULAR AUTOMATON MODEL

This paper extends a cellular automaton model, named modified comfortable driving (MCD) model, to a two-lane roadway. A symmetric lane-changing rule set has been proposed (Set I). The fundamental diagram, the lane-changing frequency and space-time plots are presented. It is found that for the two-lane model, there exists a density range in which phase separation between synchronized flow and wide-moving jams on one lane, and between light synchronized flow and heavy synchronized flow on the other lane, can be maintained for quite long periods of time. In this density range, (i) the outflow from jams is synchronized flow; (ii) wide moving jams are sparse. These are consistent with the empirical observation. We also investigate a slightly different lane-changing rule Set II in which stopped vehicles are not allowed to change lane. It is shown that in this case, the phase separation, between free flow and wide moving jams on one lane and between free flow and heavy synchronized flow on the other lane, can be maintained for sufficiently long periods of time. Consequently, the flux is enhanced comparing to that of rule Set I.

The effect of attachment and detachment on totally asymmetric exclusion processes with junctions

In this paper, we investigate totally asymmetric exclusion processes on lattices with junctions, considering random particle attachment and detachment in the bulk. Particles randomly attach to the bulk with the rate ωA and detach from the bulk with the rate ωD. Setting K = ωA/ωD, we study three cases: K>1, K = 1 and K 1, additional phases are observed in the case of K≤1. Moreover, it is shown that at a fixed K, the phase diagram structure changes with the increase of ωD. A mean-field analysis has been carried out and the analytic results are in good agreement with the simulation results.

TRAFFIC DYNAMICS IN A TWO-LANE MIXED TRAFFIC SYSTEM: EFFECT OF FOUR LANE CHANGING REGULATIONS

This paper investigates traffic dynamics of two-lane mixed traffic flow system composed of cars and buses, which are characterized by different lengths and different maximum velocities. Four lane changing regulations are studied, which reveals effect of lane changing ban, symmetric and asymmetric lane changing rules on traffic flow characteristics (flow rate, carry capability, lane changing frequency, and lane usage). We expect that our results could be useful for traffic management.

On the Approximation Solution of a Cellular Automaton Traffic Flow Model and Its Relationship with Synchronized Flow

This paper studies approximation solution of a cellular automaton model. In the model, the finite size effect is trivial because the congested flow is quite homogeneous. Thus, the approximation solution of a small sized system can be regarded as solution of large system. We have investigated the approximation solution of a small traffic system with two vehicles. The analytical result is in good agreement with simulation. Finally, it is demonstrated that the homogeneous congested flow is closely related to synchronized flow.