Disorder effect on the traffic flow behavior
LMPHE, Département de Physique, Faculté des Sciences, Université Mohammed V-Agdal , B.P. 1014, Rabat, Morocco
Corresponding author: a email@example.com
Revised: 11 February 2008
Published online: 7 March 2008
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 and on the fundamental diagram. It is Found that the small delay times have almost no effect, while, for sufficiently large delay time , the current profile displays qualitatively five different forms, depending on , and the fractions ff and fs 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 . Furthermore there exist, a critical value of above which the meta-stability and hysteresis appear. The effects of disorder due to drivers behaviors have been introduced through a random delay time allowing the car to reach its optimal velocity traffic flow models with open boundaries. In the absence of the variation of the delay time , 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 and 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 and the current remains constant (plateau) for , 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.
PACS: 45.70.Vn – Granular models of complex systems; traffic flow / 45.50.-j – ynamics and kinematics of a particle and a system of particles / 45.70.Mg – Granular flow: mixing, segregation and stratification / 47.57.Gc – Granular flow
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2008