Modeling of Double-Lane Roundabouts Using the Waiting System

Abstract

Roundabouts are designed to improve intersection safety and efficiency, and in Malaysia, most are double-laned. However, existing methods for analysing roundabout performance remain limited. Some focus only on traffic parameters or signal controls without considering density and flux variations, while others treat double-lane roundabouts as separate, independent lanes or restrict analysis to entry and exit points. These approaches do not fully capture the dynamics of a complete double-lane four-arm roundabout. To address this gap, a new double-lane roundabout model is derived. The model represents the roundabout as two interconnected rings with four arms and incorporates a waiting system to better reflect real traffic conditions. It is formulated using hyperbolic partial differential equations within a macroscopic framework and solved numerically with the Godunov method. The Courant-Friedrichs-Lewy (CFL) condition is applied to ensure stability and accuracy of the simulations. Simulation results demonstrate logical changes in Total Travel Time and Total Waiting Time under different parameter settings, reflecting realistic traffic flow behaviour. This model provides a more comprehensive representation of double-lane roundabouts, offering valuable insights for researchers as well as government and private agencies in evaluating roundabout performance.