The effect of mixture lengths of vehicles and braking on the traffic flow behavior in two-lane roadway

Using a numerical simulation, we study the effect of the mixture lengths of vehicles on a traffic flow in a two-lane roadway, for periodic boundaries in parallel dynamics. A deterministic cellular automaton which is an extended version of the one-dimensional asymmetric model is used to take into account the exchange of the vehicles between the two lanes. The variation of mean velocity and flow in a two-lane roadway versus the initial concentration C1, of vehicles in first lane, are studied for different values of the initial ratio f, between cars in lane 2 and vehicles in lane 1, and initial concentration n of trucks in lane 1. The presence of trucks has an important effect on phase transition between the maximal velocity phase and high density one. Indeed, the maximal current value decreases with increasing the concentration of trucks, and occurs at higher values of the initial density of vehicles in lane 1. The phase diagram (f,C1) established for different values of n. The maximal velocity phase increases by increasing the concentration of trucks in the circuit. Also, to approach more the reality, we have taken into account the human factor by introducing random rates. The random noises have a great effect on the results compared to those obtained in the deterministic case. Indeed, the current flow decreases and the first-order transition (LDP)-(HDP) is replaced by a second-order one in the presence of random noises

Multicritical Behaviours in One-Dimensional Traffic Flow

The effect of the on-ramp and off-ramp positions i1 and i2 , respectively, on the one dimensional-cellular automaton traffic flow behaviour, is investigated numerically. The on-ramp and off-ramp rates at  i1 and i2 are α0 and β0 , respectively. However, in the open boundary conditions, with injecting and extracting rates α and β and using parallel dynamics, several phases occur, depending on the position of i1 by respect to i2. Namely, low density phase (LDP), intermediate density phase (IDP), plateau current phase (PCP) and high density phase (HDP). Furthermore, critical, tricritical and multicritical behaviours take place in the ( i1 , α0 ) phase diagrams.The effect of the on-ramp and off-ramp positions i1 and i2 , respectively, on the one dimensional-cellular automaton traffic flow behaviour, is investigated numerically. The on-ramp and off-ramp rates at  i1 and i2 are α0 and β0 , respectively. However, in the open boundary conditions, with injecting and extracting rates α and β and using parallel dynamics, several phases occur, depending on the position of i1 by respect to i2. Namely, low density phase (LDP), intermediate density phase (IDP), plateau current phase (PCP) and high density phase (HDP). Furthermore, critical, tricritical and multicritical behaviours take place in the ( i1 , α0 ) phase diagrams