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Najem Moussa

Publications and source records attributed to Najem Moussa.

2 recordsLinked to original sources

Relaxation dynamics in congested traffic.

We investigate the relaxation dynamics in congested traffic when starting from the "megajam" initial condition (all cars standing in one big cluster of density 1) in the framework of the traffic model proposed by Nagel and Schreckenberg. On the one hand, a simple comparison of the time evolutions of some relevant traffic quantities shows that the slowest relaxing quantity is the density of "go and stop" cars rather than the average velocity of cars. On the other hand, we find that the relaxation time diverges in the form of a power law tau approximately tau(0) p(-beta) . A simple theoretical argument predicts that the exponent " beta " is equal to 1. This prediction is consistent with the numerical result.

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Car accidents in cellular automata models for one-lane traffic flow.

Conditions for the occurrence of car accidents are introduced in the Nagel-Schreckenberg model. These conditions are based on the thought that a real accident depends on several parameters: an unexpected action of the car ahead (sudden stop or abrupt deceleration), the gap between the two cars, the velocity of the successor car and its delayed reaction time. We discuss then the effect of this delayed reaction time on the probability of traffic accidents. We find that these conditions for the occurrence of car accidents are necessary for modeling realistic accidents.

Journal Article↗