Modeling Traffic Flow on Multi-Lane Road: Effects of Lane-Change Manoeuvre Due to Ramps and Weaving Sections

Abstract

Traffic breakdown is the main cause of vehicle traffic congestion in multi-lane roads due to highway bottlenecks such as lane-drops, on and off-ramps. In this study, the nature of traffic congestion and phase transition at the highway bottlenecks is explained. A multi-lane macroscopic traffic flow model of Aw-Rascle type is derived from the kinetic traffic flow model in which the lane-change terms are expressed explicitly. This is achieved by first developing the Kinetic traffic flow interaction operators and then applying the method of moments to get the corresponding macroscopic equations. For simulation of the traffic congestion, we consider a highway with three traffic lanes that have stationary bottlenecks. The macroscopic model equations for each lane are solved numerically using finite volume method (Godunov scheme), whereby the Euler’s method is used for the source term. The results of the simulations of the congestion near and within the bottlenecks are presented in form of graphs and space-time plots. These results show that vehicle lane-change manoeuvre near the bottlenecks lead to traffic breakdown and congestion on the lane adjacent to the bottlenecks compared to the other express lanes in the highway. This prompts the following vehicles moving in the outermost lane to either slow down upon reaching the disturbance region or change to the other lanes before they reach the merging region. The model results provide important insight into improving the road network design and safety management strategies especially when new roads are constructed.