Traffic model with quenched disorder

Using numerical simulations, we study the effects of defects in the road and of jumping rate Delta t on the phase diagram J-rho. For different level of disorder, the space-time evolution of particles displays "waves" for both low density and high density phases. Besides, there exist two critical values of density, a lower critical value rho(c1) and a upper critical value rho(c2), in between the current is constant and reaches its maximal value J(max) which increases with increasing the jumping rate Delta t and/or the degree of disorder c. The critical densities rho(c1) and rho(c2) depend on the values of Delta t and c. Indeed, when increasing Delta t and/or c, rho(c1) increases and rho(c2) decreases. The known results for the perfect road are also obtained. (C) 1999 Elsevier Science B.V.