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In this paper, we propose a cellular automaton model to investigate the traffic flow characteristics in the traffic circle system with adaptive traffic lights control. The traffic flow in the circulating lane was evaluated and depending on it the traffic lights lit red in the entry lanes to reduce the coming traffic. The density and the satisfaction rate were used as feedback to control the traffic flow in the circulating lane. It is found that both parameters (i.e. the density and the satisfaction rate in the circulating lane), if they are used as a criterion to control the coming traffic from entry lanes, promote the throughput in the traffic circle system. Traffic flow for the traffic circle system without using the traffic lights was investigated. In this case, we find that the traffic flow in the system is characterized by three phases, namely, gridlock, congestion, and free flow. The gridlock phase is predominant over the other phases. Furthermore, with the use of the adaptive traffic lights, the gridlock phase has vanished and the maximum current, jammed, and congestion phases take place. The density criterion shows good performance as compared with the satisfaction rate criterion in terms of the lengths of the red cycle. The capacity is also investigated. The space-time configurations were given to understand the microscopic interaction between vehicles. [ABSTRACT FROM AUTHOR]

In this paper, we propose a cellular automaton model to simulate traffic flow controlled by a series of traffic lights. The synchronized traffic light and the green wave light strategies were investigated. The spatiotemporal diagrams, energy dissipation, and CO2 emission of the system were presented. Our simulations are conducted to clarify the difference between both strategies and their effects on the traffic flow and the CO2 emission. We found that the traffic flow depends mainly on the strategy used for managing the traffic lights as well as on the parameters of the traffic lights, namely the cycle length, the number of traffic lights and the length of the system. The fundamental diagram has barely the same characteristics for both methods and it depends on the combination of the parameters of the system. We find that the green wave is more convenient for the management of a series of traffic lights than the synchronized control strategy in terms of throughput, especially for large-sized systems. Unlike in terms of CO2 emission and energy dissipation, both control strategies outperform each other depending on the density regions and the parameters of the system. Finally, we investigate the effect of both cycles (i.e. red and green) for the synchronized control method on the CO2 emission. It is found that the green cycle generates often a series of acceleration events that increase CO2 emission. [ABSTRACT FROM AUTHOR]

In this paper, we present a cellular automata model to depict the traffic characteristics at such a nonsignalized -shaped intersection in the presence of pedestrian crossings. The vehicular traffic flow characteristics with different parameters are studied. Throughput, phase diagrams, space-time and density profiles are built to point various traffic states and the phase transition features. The principal finding of the simulation are as follows: (1) The presence of crossing pedestrians has a significant influence on the vehicular traffic and the system performance, (2) The intersection capacity has a close relevance with the state of the weaving section. The smaller the interactions are at the weaving section, the higher the capacity and (3) In order to have a higher system ability, the crosswalk location should not be far from the yield line of the weaving section. [ABSTRACT FROM AUTHOR]

This paper proposes a vehicle–pedestrian cellular automata model to investigate the characteristics of the mixed traffic at a single lane roundabout. The roundabout boundary is controlled by the injecting rates α 1 , α 2 and the extracting rate β whereas pedestrians are generated with arrival probability P cr . The pedestrian and vehicle flux are calculated in terms of rates. Also, the phase diagrams of the system in the ( α 1 , P cr ) and ( α 1 , β ) spaces are constructed. The results show that, the gridlock state is reached only when the pedestrians have the right of way over vehicles, while the maximum current state is reached when including a pedestrians’ crossing decision rule. Likewise, we have found that the crosswalk location play a chief role in improving the dynamic characteristics of pedestrian and vehicle flux. Furthermore, it has turned out that the traffic is sensitive to the driver behavior. [ABSTRACT FROM AUTHOR]

Using cellular automata (CA) Nagel–Schreckenberg (NaSch) model, we numerically study the probability Pac of the occurrence of car accidents at nonsignalized intersection when drivers do not respect the priority rules. We also investigated the impact of mixture lengths and velocities of vehicles on this probability. It is found that in the first case, where vehicles distinguished only by their lengths, the car accidents start to occur above a critical density ρc. Furthermore, the increase of the fraction of long vehicles (FL) delays the occurrence of car accidents (increasing ρc) and increases the risk of collisions when ρ > ρc. In other side, the mixture of maximum velocities (with same length for all vehicles) leads to the appearance of accidents at the intersection even in the free flow regime. Moreover, the increase of the fraction of fast vehicles (Ff) reduces the accident probability (Pac). The influence of roads length is also studied. We found that the decrease of the roads length enhance the risk of collision. [ABSTRACT FROM AUTHOR]

In this paper, we propose a stochastic Cellular Automata (CA) model to study traffic flow at a single-lane urban roundabout (resp. traffic circle) of N entry points (resp. exit points), the entry points are controlled by rates α 1 and α 2 while the removal rates from the exit points are denoted by β . The traffic is controlled by a self-organized scheme. Based on computer simulation, density profiles, global density and current are calculated in terms of rates. Furthermore, the phase diagrams for roundabout as well as traffic circle are constructed. It has turned out that the phase diagrams consist essentially of two phases namely free flow and jamming. It is noted that the typology of the phase diagrams of the roundabout is not similar to it in the traffic circle. Furthermore, we have compared the performance of the two systems in terms of the geometrical properties and the number of entry points. [ABSTRACT FROM AUTHOR]

Connected vehicles (CVs) have led to innovative changes in the transportation field. In this wise, an extended CA model was established incorporating the CVs and regular vehicles to investigate a roundabout traffic flow under the open boundary condition. The throughput and the phase diagrams of the system in the ( α 1 , α 2 ) area is constructed in both cases: with and without CVs. The density profile and the capacity are also calculated. The simulation findings show that CVs presentation changes the traffic dynamics, enhancing roundabout capacity in accordance with the CVs penetration rate. Furthermore, it is found that roundabout size plays a dominant role in its performance where it suggests that the midsized roundabouts operate more optimally. Another relevant aspect is the short sized of Splitter Island shows a better performance. Moreover, the traffic dynamics is negatively (resp. positively) correlated to the probability of displaying indicator P ind as well as the probability of aggressive driving behavior of regular vehicles (resp. the cooperation probability P cop ). [ABSTRACT FROM AUTHOR]

We propose a traffic flow model which takes into account the disorder in the length and the maximal speed of cars. Using cellular automaton model in parallel dynamics we have studied the behavior of traffic flow, especially the condition of formation (active phase) and the dissociation (absorbing phase) of platoons. It is found that the transition from active to absorbing phase depend on the length of the slow vehicles L2. Indeed, the transition is discontinuous for L2 = 1 and continuous when L2 > 1. In the later case, the critical exponent is calculated near the transition density, and the space-time diagram shows the presence of the two phases. Furthermore, we have found that the fundamental diagram exhibit a plateau which depend on the size of the system. [ABSTRACT FROM AUTHOR]

The effects of some disorders, on the traffic flow behavior, are studied numerically. Especially, the effect of mixture of vehicles of different velocities and/or lengths, the effects of different drivers reactions, the position and the extraction rate of off-ramp in the free way. Using a generalized optimal velocity model, for a mixture of fast and slow vehicles, we have investigated the effect of delay times τ f and τ s on the fundamental diagram. It is Found that the small delay times have almost no effect, while, for sufficiently large delay time τ s , the current profile displays qualitatively five different forms, depending on τ f , τ s and the fractions f f and f s of the fast and slow cars, respectively. The velocity (current) exhibits first-order transitions at low and/or high densities, from freely moving phase to the congested state, and from congested state to a jamming one, respectively. The minimal current appears in intermediate values of τ s . Furthermore there exist, a critical value of τ f above which the meta-stability and hysteresis appear. The effects of disorder due to drivers behaviors have been introduced through a random delay time τ allowing the car to reach its optimal velocity traffic flow models with open boundaries. In the absence of the variation of the delay time Δτ, it is found that the transition from unstable to meta-stable and from meta-stable to stable state occur under the effect of the injecting and the extracting rate probabilities α and β respectively. Moreover, the perturbation of the traffic flow behavior due to the off-ramp has been studied using numerical simulations in the one dimensional cellular automaton traffic flow model with open boundaries. When the off-ramp is located between two critical positions i c1 and i c2 the current remains constant (plateau) for β0 c1 < β0 < β0 c2, and the density undergoes two successive first order transitions: from high density to plateau current phase and from average density to the low one. In the case of two off-ramps, these transitions occur only when the distance between ramps, is smaller than a critical value. [ABSTRACT FROM AUTHOR]

Tollbooths are used to collect tolls and to control traffic flow. However, the presence of these tollbooths will slow down traffic, especially in heavily traveled roads. As a consequence, drivers and goods will spend more time and fuel waiting in a long queue. Unfortunately, there are a few papers in the literature, which have been addressed the effect of tollbooths on the traffic flow; whereas in this paper is, the properties of traffic flow inside the tollbooths are investigated. The proposed cellular automaton traffic model, with open boundaries, is based on some changing lane rules, which are inspired on the situations inside the toll plaza. The vehicles enter the plaza with an injecting rate α, and they leave with an extracting rate β, which is inversely proportional to the time service Tw. The simulation results show the existence of three phases in the phase diagram (α, β), namely: the low density phase, the congested phase, and the jamming phase. Furthermore, it is found that the vehicles does not spend the same time Tm in the plaza, even if they have the same time service. This analysis states clearly that the existence of the congested phase and the fluctuation Tm are due to the non-zero values of the probability P of changing the lane. Such phenomena disappear when P = 0, i.e., the drivers move without changing their lane. In other words, the human behavior (spontaneous changing lanes) is responsible for the congestion observed in the tollbooth. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the impact of connected and autonomous vehicles (CAVs) on traffic flow under various parameters. For this purpose, we propose a mixed CAV and conventional vehicle (CV) model to investigate a bidirectional two-lane traffic flow under the periodic boundary condition. The traffic flux and the phase diagrams of the system in the ( ρ 1 , ρ 2 ) area are constructed in both cases: with and without CAVs. The overtaking frequency is also calculated. The simulation findings show that the traffic capacity is greatly enhanced with the increase in the CAV penetration ratio. Owing to the cooperative driving strategy, with the increase in penetration ratio of the CAV, the portion of smooth overtaking is boosted. Furthermore, it is found that the traffic throughput is positively correlated to the speed limit of the fast vehicle where the flux increases as V max − F increases. Also, even if there is a low rate of slow moving vehicles in the system, it will have an appreciable and a significant negative influence. [ABSTRACT FROM AUTHOR]

In this paper, we propose a stochastic cellular automata model to study the traffic behavior at a single-lane roundabout. Vehicles can enter the interior lane or exit from it via intersecting lane, the boundary conditions are stochastic. The traffic is controlled by a self-organized scheme. It has turned out that depending on the rules of insertion to the roundabout, five distinct traffic phases can appear, namely, free flow, congestion, maximum current, jammed and gridlock. The transition between the free flow and the gridlock is forbidden. The density profiles are used to study the traffic pattern at the interior lane of the roundabout. In order to quantify the interactions between vehicles in the interior lane of the roundabout, the velocity correlation coefficient (VCC) is also studied. Besides, the spatiotemporal diagrams corresponding to the entry/exit lanes are derived numerically. Furthermore, we have investigated the effect of displaying signal (, as the decreases, the maximum current increases at the expense of the free flow and the jamming phase. Finally, we have investigated the effect of the braking probability on the interior lane of the roundabout. We have found that the increase of raises the spontaneous jam formation on the ring. Thus, enlarges the maximum current and the jamming phase while the free flow phase decreases. [ABSTRACT FROM AUTHOR]

Mixed traffic flux composed of crossing pedestrians and vehicles extensively exists in cities. To study the characteristics of the interference traffic flux, we develop a pedestrian-vehicle cellular automata model to present the interaction behaviors on a simple cross road. By realizing the fundamental parameters (i.e. injecting rates α 1 , α 2 , the extracting rate β and the pedestrian arrival rate α P ), simulations are carried out. The vehicular traffic flux is calculated in terms of rates. The effect of the crosswalk can be regarded as a dynamic impurity. The system phase diagrams in the ( α 1 , α P ) plane are built. It is found that the phase diagrams consist essentially of four phases namely Free Flow, Congested, Maximal Current and Gridlock. The value of the Maximal current phase depends on the extracting rate β , while the Gridlock phase is achieved only when the pedestrians generating rate is higher than a critical value. Furthermore, the effect of vehicles changing lane ( P ch 1 , P ch 2 ) and the location of the crosswalk X P on the dynamic characteristics of vehicles flow are investigated. It is found that traffic situation in the system is slightly enhanced if the location of the crosswalks X P is far from the intersection. However, when P ch 1 , P ch 2 increase, the traffic becomes congested and the Gridlock phase enlarges. [ABSTRACT FROM AUTHOR]

The speed limit signs can be used to enhance traffic safety, nevertheless, the large differences between the speed of vehicles provoked by the speed limit zone (SLZ) may increase the dissipation of energy caused by the deceleration of vehicles. In this paper, the effect of the SLZ on traffic flow and energy dissipation is investigated based on a cellular automaton model that considers the three traffic phases (free flow, synchronized flow and wide moving jams). It is found that the throughput and the energy dissipation depend strongly on the length of the SLZ as well as on the speed adopted inside the SLZ. The microscopic effect of the SLZ is also studied. The dependence of the density and the length of platoons induced by the SLZ were evaluated. The characteristic of the traffic flow can be also evaluated with the energy dissipation. For high densities, the effect of the SLZ becomes seldom on the flow, however, the energy dissipation shows salient features, which can be used as an indicator of traffic phases. [ABSTRACT FROM AUTHOR]

In this paper, we investigated a non-signalized T-shaped intersection using the cellular automata model under the open boundary condition. Two different priority rules at intersection are introduced (Rule 1, Rule 2) to eliminate the jam-packed state. Phase diagram and its variation with the ratios of right and/or left turning vehicles are investigated. The space-time and the density profiles are also studied. The simulation results indicate that the system does not show the same performance under different priority rules, where Rule 1 (resp. Rule 2) can be better than Rule 2 (resp. Rule 1) according to the ratios of turning vehicles. [ABSTRACT FROM AUTHOR]

Using the cellular automata model, we numerically study the traffic dynamic in a single lane roundabout system of four entry/exit points. The boundaries are controlled by the injecting rates α 1 , α 2 and the extracting rate β . Both the system with and without Splitter Islands of width L sp are considered. The phase diagram in the ( α 1 , β ) space and its variation with the roundabout size, P agg (i.e. the probability of aggressive entry), and P exit (i.e. the probability of preferential exit) are constructed. The results show that the phase diagram in both cases consists of three phases: free flow, congested and jammed. However, as L sp increases the free flow phase enlarges while the congested and jammed ones shrink. On the other hand, the short sized roundabout shows better performance in the free flow phase while the large one is more optimal in the congested phase. The density profiles are also investigated. [ABSTRACT FROM AUTHOR]

In this paper, using the Nagel-Schreckenberg model, we numerically investigate the probability of entering/circulating car accidents to occur at single-lane roundabout under the expanded open boundary. The roundabout consists of N on-ramps (respectively, off-ramps). The boundary is controlled by the injecting rates and the extracting rate . The simulation results show that, depending on the injecting rates, the car accidents are more likely to happen when the capacity of the rotary is set to its maximum. Moreover, we found that the large values of rotary size L and the probability of preferential are reliable to improve safety and reduce accidents. However, the usage of indicator, the increase of and/or N provokes an increase of car accident probability. [ABSTRACT FROM AUTHOR]

Traffic flow behavior and velocity correlation in a bidirectional two lanes road are studied using Cellular Automata (CA) model within a mixture of fast and slow vehicles. The behaviors of the Inter-lane and Intra-lane Velocity Correlation Coefficients (V.C.C.) due to the interactions between vehicles in the same lane and the opposite lane as a function of the density are investigated. It is shown that high densities in one lane lead to large cluster in the second one, which decreases the Intra-lane velocity correlations and thereby form clusters in the opposite lane. Moreover, we have found that there is a critical density over which the Inter-lane V.C.C. occurs, but below which no Inter-lane V.C.C. happens. The spatiotemporal diagrams correspond to those regions are derived numerically. Furthermore, the effect of the overtaking probability in one lane on the Intra-lane V.C.C. in the other lane is also investigated. It is shown that the decrease of the overtaking probability in one lane decreases slightly the Intra-lane V.C.C. at intermediate density regimes in the other lane, which improves the current, as well as the Inter-lane V.C.C. decreases. [ABSTRACT FROM AUTHOR]

In this paper, using Nagel-Schreckenberg model we study the on-ramp system under the expanded open boundary condition. The phase diagram of the two-lane on-ramp system is computed. It is found that the expanded left boundary insertion strategy enhances the flow in the on-ramp lane. Furthermore, we have studied the probability of the occurrence of car accidents. We distinguish two types of car accidents: the accident at the on-ramp site (Prc) and the rear-end accident in the main road (Pac). It is shown that car accidents at the on-ramp site are more likely to occur when traffic is free on road A. However, the rear-end accidents begin to occur above a critical injecting rate αc1. The influence of the on-ramp length (LB) and position (xC0) on the car accidents probabilities is studied. We found that large LB or xC0 causes an important decrease of the probability Prc. However, only large xC0 provokes an increase of the probability Pac. The effect of the stochastic randomization is also computed. [ABSTRACT FROM AUTHOR]

In this paper, we propose a two-lane cellular automata model that explains the relationship between traffic-related parameters and likelihood of accidents P a c at a signalized intersection. It is found that, the risk of collision rises as well as the lane-changing probability P c h g augments, besides, the accidents and inflow α show a nonlinear relationship. Moreover, P a c exhibits three different phases (I, II and III) depending on α. Likewise, the system exhibits a second (first) order transition from phase I to phase II when P c h g >0 ( P c h g = 0). Nevertheless, the transition from phase II to phase III is of first (second) order when P c h g > 0 ( P c h g = 0). In addition, the result analysis shows that the distribution of accidents according to the intersection sites is not equiprobable. Furthermore, when the traffic arriving strength is not very high, the green light length of one road should be increased to restrain P a c and enhance the road safety. Finally, the model results illustrated that the traffic at the intersection is more dangerous adopting asymmetric lane-changing rules than symmetric ones. • We investigated the risk of accidents at a signalized intersection using CA model. • Lane-changing probability has a significant effect on the risk of accidents. • The probability of accidents exhibits three phases depending on the injection rate. • Over 50% of all accidents occur at the fourth site of the intersection. • Traffic intersection is more dangerous adopting asymmetric rules than symmetric ones. [ABSTRACT FROM AUTHOR]

The correlation between the velocity of two successive vehicles as a function of time headway is studied in the one-dimensional cellular automata (CA) NaSch model within parallel dynamic update. It is found that a strong correlation occurs in short time headway. The behavior of the correlation velocity as a function of the car density in different traffic states is also investigated. Moreover, our study is also extended to a more complicated situation where the two vehicles are separated by a number n of other vehicles. It is shown that the velocity correlation coefficient depends strongly on the number n of vehicles in between and on their positions. [ABSTRACT FROM AUTHOR]

In this paper, we study the probability of car accidents in the modified Nagel–Schreckenberg (mNaSch) under the periodic boundary condition. In order to understand the quality of interaction between vehicles in each phase of the mNaSch, the velocity correlation coefficients were investigated. The effect of the evacuation of damaged vehicles was also studied. The fundamental diagram of the system is constructed in both cases with and without the evacuation. We found that the synchronized phases in the mNaSch are manifested into two aspects. In the first phase, the velocity correlation coefficients are zero where all vehicles move at the same speed. Hence, in the other phase, the speed of vehicles shows a synchronization as the form of clusters of moving vehicles where two speeds predominate simultaneously and the velocity correlation coefficients are higher. In addition, the car accidents in the modified mNaSch depend strongly on the initial configuration especially, if we consider those car accidents really happening in the system. The evacuation of damaged vehicles enhances the traffic situation and qualitatively changes the traffic phases in the mNaSch. [ABSTRACT FROM AUTHOR]

In this paper, we propose a cellular automata model to study the energy dissipation in the roundabout system. The energy dissipation and the phase diagram of the system in the space (α , β) are constructed. The energy dissipation profile (SE d (i)), and the effect of the rate γ (i.e., the rate of vehicles with no aimed exit point) and the probability P exit of choosing the next exit point to leave the circulating lane on the energy dissipation are shown. The simulation results show that the energy dissipation explains the nature of the phases, the quasi-free-flow (Q-FF) phase take place on the free flow phase because some vehicles decelerate at the entry point. Likewise, the results also indicate that the energy dissipation takes small values with the increases of the two probability γ and P exit which enhance the environmental statutes of the roundabout system. [ABSTRACT FROM AUTHOR]

Using the cellular automata Nagel–Schreckenberg (NaSch) model, we numerically study the impact of traffic lights on the probability of car accidents ( P ac ) at the intersection of two roads. It is found that, the probability P ac is more stable with variation of the green light (T) when the symmetric lights are adopted. Moreover, simulation results show the existence of a critical time T c , below which (T < T c ) P ac increases as the injection rate (α) increases, however, above which (T > T c ) the growing of α has for effect the decrease of P ac . Furthermore, the decrease of P ac is almost always accompanied by a loss of the flux, especially with asymmetrical lights. To overcome this problem, we proposed a strategy that can greatly increase the flux and keep the probability P ac as small as possible, especially for the low and high injection rates. [ABSTRACT FROM AUTHOR]

In this paper, we propose a stochastic cellular automata (CA) model to study traffic dynamic at a single-lane traffic circle of entry/exit points. The boundaries are controlled by the injecting rates , and the extracting rate . Both the cases with and without the splitter islands of width are considered. The phase diagrams in the space are constructed and the density profiles are also investigated. The variation of the phase diagram with the traffic circle size , the number of entry point , and the time needed for drivers to change their exit willingly is studied. The results show that the phase diagram in both cases consists essentially of three phases namely free flow, congestion and gridlock. However, the large sized traffic circle shows better performance in the free flow phase, in contrary, the increase of enlarges the congestion and the gridlock phases. We have also found that the decrease of enhances the traffic flow situation in the traffic circle. Furthermore, as the increases, the free flow phase enlarges while the congestion and gridlock ones shrink. [ABSTRACT FROM AUTHOR]

For the purposes of optimizing traffic flow composed of different types of vehicles, it is important to understand the interactions between them. This paper proposes a cellular automata model to investigate a bidirectional two-lane traffic flow under the periodic boundary condition. The vehicle flux and the phase diagrams of the system in the () space are constructed by applying two different overtaking models (symmetric, asymmetric). The inter-lane correlation and the overtaking frequency are also studied. The simulation results show that the variation of the density of one lane has an apparent influence on the traffic of the adjacent lane. Furthermore, it is found that the phase diagram on both models is classified into several regions. Thus, for the symmetric model, as the overtaking probability increases, the traffic on the system becomes better. Likewise, the results also indicate that the asymmetric model can effectively enhance the traffic capacity and alleviate the congested state. [ABSTRACT FROM AUTHOR]

Using the extended Nagel-Schreckenberg (NS) model, we numerically study the impact of the heterogeneity of traffic with speed limit zone (SLZ) on the probability of occurrence of car accidents . SLZ in the heterogeneous traffic has an important effect, typically in the mixture velocities case. In the deterministic case, SLZ leads to the appearance of car accidents even in the low densities, in this region increases with increasing of fraction of fast vehicles . In the nondeterministic case, SLZ decreases the effect of braking probability in the low densities. Furthermore, the impact of multi-SLZ on the probability is also studied. In contrast with the homogeneous case [X. Li, H. Kuang, Y. Fan and G. Zhang, Int. J. Mod. Phys. C 25 (2014) 1450036], it is found that in the low densities the probability without SLZ is low than with multi-SLZ . However, the existence of multi-SLZ in the road decreases the risk of collision in the congestion phase. [ABSTRACT FROM AUTHOR]

We use a cellular automata approach to describe the interactions of the immune system with the human immunodeficiency virus (HIV). We study the evolution of HIV infection, particularly in the clinical latency period. The results we have obtained show the existence of four different behaviours in the plane of death rate of virus–death rate of infected T cell. These regions meet at a critical point, where the virus density and the infected T cell density remain invariant during the evolution of disease. We have introduced two kinds of treatments, the protease inhibitors and the RT inhibitors, in order to study their effects on the evolution of HIV infection. These treatments are powerful in decreasing the density of the virus in the blood and the delay of the AIDS onset. [Copyright &y& Elsevier]