An Analysis of A Three-Phase Versus A Four-Phase Traffic Lights Regulation for A Four-Leg Intersection

S R Pudjaprasetya ,Dear Michiko Noor

doi:10.22342/jims.26.2.823.192-201

Abstract

Traffic management of intersections is an important factor that can determine traffic density at the intersection, as well as its surrounding. Long traffic queues we encounter in daily life, were often caused by ineffectiveness of traffic lights management of the cross sections.In this article, an analytic study of traffic light management of a four-leg intersection, based on the kinematic LWR model, was presented. Comparison was based on observing the end of queues over three cycles of red-green lights, under the assumption of a constant traffic flux. On every leg of the intersection, the end of the queues were obtained from characteristic lines of the shock waves.From these observations, the three phase regulation was preferred over the four-phase one. Finally, a case study of Taman Sari - Baltos intersection located in Bandung City, Indonesia, was discussed. Parameter values used in these simulations were obtained from direct observation.

Highlights

People living in densely populated urban areas encounter traffic congestion almost every day
The three-phase and four-phase traffic light regulations have been analyzed using the kinematic model with the Underwood flux function
Graphical method has been implemented, in which traffic condition during green and red lights were associated as points on the flux curve, and the growth of traffic queue behind the intersection was determined by a segment line on the flux curve

Summary

Introduction

People living in densely populated urban areas encounter traffic congestion almost every day. The kinematic equation is a conservative equation that has shock wave and rarefaction wave solutions These solutions can be constructed using the method of characteristics. In [9] this kinematic model was used to compare the performance of traffic lights or a roundabout in a cross section. Another method using a second-order equations, analogous to dynamics of fluid flow has been proposed and discussed in [1, 2, 10].

Kinematic LWR model and the graphical approach

Analysis of a three-phase versus a four-phase

A case study

Concluding remarks