A new stochastic cellular automaton model on traffic flow and its jamming phase transition

Metastability due to a branching-merging structure in a simple network of an exclusion process

We investigate a simple network, which has a branching-merging structure, using the totally asymmetric simple exclusion process, considering conflicts at the merging point. For both periodic and open boundary conditions, the system exhibits metastability. Specifically, for open boundary conditions, we observe two types of metastability: hysteresis and a nonergodic phase. We analytically determine the tipping points, that is, the critical conditions under which a small disturbance can lead to the collapse of metastability. Our findings provide insights into metastability induced by branching-merging structures, which exist in all network systems in various fields.

Cognitive anticipation cellular automata model: An attempt to understand the relation between the traffic states and rear-end collisions

We have investigated the accident's statistics of Europe and North America that are provided by the UN. This investigation has shown that accidents due to the traffic represent around 50 % of the total number of accidents every year. Among them, rear-end collisions hold a 20 % share. These numbers display the fact that the interaction between drivers can be held responsible of those incidents. In this respect, we have explored the reasons behind the conflict situations that may be responsible of the occurrence of rear-end collisions by the mean of a cognitive psychology based cellular automata model. Indeed, through field experiments performed by an embedded camera, we have extricated a psychological cognitive process of anticipation. We have defined the latter as the tendency of drivers to accelerate based on the history of their predecessor. Then, we have exploited the tools of the physics of traffic by which we have developed a CA-model that take into consideration this process. As a result, we were able to generate those incidents' situations. By considering two types of drivers: conservative who respect the learned information about the safe manoeuvres but make mistakes or aggressive who violate those secure processes, we have proved the complexity of the relationship between the states of the traffic flow and the drivers' behaviours. In fact, we have shown that rear-end collisions are a result of the anticipation as a response of the drivers to the traffic conditions: the congestion. Moreover, we have also highlighted an improvement of the flow in the congested state up to 11 % due to the anticipation, but that can only be achieved through vehicle-to-vehicle communication. Finally, we have investigated the hot spots. We have found that the traffic perturbations, that generate those hot spots and can be responsible of collisions, are more likely to be located away in the downstream direction. The distance between the two locations depends on the traffic density. This difference between the positions of the traffic perturbation and the hot spot has showcased the complexity, in time and space, of the transmission and the reception of deceleration information by the drivers.

Totally asymmetric simple exclusion process with a time-dependent boundary: interaction between vehicles and pedestrians at intersections

Interaction between vehicles and pedestrians is seen in many areas such as crosswalks and intersections. In this paper, we study a totally asymmetric simple exclusion process with a bottleneck at a boundary caused by an interaction. Due to the time-dependent effect originating from the speed of pedestrians, the flow of the model varies even if the average hopping probability at the last site is the same. We analyze the phenomenon by using two types of approximations: extended two-cluster approximation and isolated rarefaction wave approximation. The approximate results capture intriguing features of the model. Moreover, we discuss the situation where vehicles turn right at the intersection by adding a traffic light at the boundary condition. The result suggests that pedestrian scrambles are valid to eliminate traffic congestion in the right-turn lane.