A Merging Control of Vehicles on PRT System and Analysis of Double Queues

Abstract

This paper deals with merging sections of Personal Rapid Transit systems. Several schemes have been proposed for the control of vehicles in PRT systems. In quasi-synchronous control systems, one flow of traffic must form a queue at a merging section in order to avoid the collision of vehicles. In other words, a queue is formed on one of the lines, which is called the sub line; the other line is called the main line. Basically, vehicles on the main line have priority. We propose a control strategy whereby vehicles on the main line are usually not stopped; vehicles on the main line are only stopped when the number of waiting vehicles on the sub line exceeds some specific number. Therefore, double queues are formed on the main line and the sub line, respectively. This paper presents a fundamental discussion of the effects of the double queues, by assuming a simple model of the merging section and by analyzing the relation between traffic density and the behavior of traffic i.e., the mean queue length and the queuing delay.