arXiv subjects

Najem Moussa

Publications and source records attributed to Najem Moussa.

5 recordsLinked to original sources

arXiv2009

Simulation study of traffic accidents in bidirectional traffic models

Conditions for the occurrence of bidirectional collisions are developed based on the Simon-Gutowitz bidirectional traffic model. Three types of dangerous situations can occur in this model. We analyze those corresponding to head-on collision, rear-end collision and lane-changing collision. Using Monte Carlo simulations, we compute the probability of the occurrence of these collisions for different values of the oncoming cars density. It is found that the risk of collisions is important when the density of cars in one lane is small and that of the other lane is high enough. The influence of different proportions of heavy vehicles is also studied. We found that heavy vehicles cause an important reduction of traffic flow on the home lane and provoke an increase of the risk of car accident.

physics.soc-ph↗

arXiv2009

Simon-Gutowitz bidirectional traffic model revisited

The Simon-Gutowitz bidirectional traffic model (Phys. Rev. E 57, 2441 (1998)) is revisited in this letter. We found that passing cars get stuck with oncoming cars before returning to their home lanes. This provokes the occurrence of wide jams on both lanes. We have rectified the rules for lane changing. Then, the wide jams disappear and the revisited model can describe well the realistic bidirectional traffic.

physics.soc-ph↗

arXiv2008

Metastable States in Two-Lane Traffic Flow Models With Slow-To-Start Rule

Using computer simulations, we show that metastable states still occur in two-lane traffic models with slow to start rules. However, these metastable states no longer exist in systems where aggressive drivers (\textit{which do not look back before changing lanes}) are present. Indeed, the presence of only one aggressive driver in the circuit, triggers the breakdown of the high flow states. In these systems, the steady state is unique and its relaxation dynamics should depend on the lane changing probability $p_{ch}$ and the number of aggressive drivers present in the circuit. It is found also that the relaxation time $τ$ diverges as the form of a power-law : $τ\propto p_{ch}^{-β}, β=1$.

physics.soc-ph↗

arXiv2006

Biham-Middleton-Levine Traffic Model With Origin-Destination Trips

We extended the Biham-Middleton-Levine model to incorporate the origin and destination effect of drivers trips on the traffic in cities. The destination sites are randomly chosen from some origin-destination distances probability distribution "ODDPD". We use three different distributions: exponential, uniform and power-law. We consider two variants of the model. In conserved particles model (Model A), drivers continue their travelling even if they reached their destinations. In non-conserved particles model (Model B), a driver which reaches its destination disappears with rate $β$. It is found that the traffic dynamics in model A and the evacuation processes in model B are greatly influenced by the ODDPD. On one hand, we found that we can adjust the ODDPD to enhance the road capacity of the city and to minimize the arrival times of drivers in particles conserved system and to optimize the evacuation time of drivers in non-conserved case. On the other hand, we find that, independently on the ODDPD, the evacuation time $T$ of drivers diverges in the form of a power law $T \propto β^{-ν}$, with $ν=1$.

physics.soc-ph↗

arXiv2005

A 2-Dimensional Cellular Automaton for Agents Moving from Origins to Destinations

We develop a two-dimensional cellular automaton (CA) as a simple model for agents moving from origins to destinations. Each agent moves towards an empty neighbor site corresponding to the minimal distance to its destination. The stochasticity or noise ($p$) is introduced in the model dynamics, through the uncertainty in estimating the distance from the destination. The friction parameter $"μ"$ is also introduced to control the probability that the movement of all agents involved to the same site (conflict) is denied at one time step. This model displays two states; namely the freely moving and the jamming state. If $μ$ is large and $p$ is low, the system is in the jamming state even if the density is low. However, if $μ$ is large and $p$ is high, a freely moving state takes place whenever the density is low. The cluster size and the travel time distributions in the two states are studied in detail. We find that only very small clusters are present in the freely moving state while the jamming state displays a bimodal distribution. At low densities, agents can take a very long time to reach their destinations if $μ$ is large and $p$ is low (jamming state); but long travel times are suppressed if $p$ becomes large (freely moving state).

physics.soc-ph↗