Transfer Optimization of a Urban Bus Transit Network

Abstract

Transfer optimization often becomes necessary in the planning of the

urban bus transit systems due to the non-availability of the direct routes.

Most of the urban bus transit operators cannot provide the direct routes

because of inadequate demand. In this paper an algorithm for transfer optimization

is presented. The algorithm takes into account the time differences

in the arrival and departure times of the connecting buses. Besides it can

consider all the transfers nodes in the network. A waiting time function that

adequately penalizes the excessive transfer time is used. Finally the application

of the algorithm is demonstrated on the buses operated by Durban

Transport in the city of Durban, South Africa.

Keywords: bus transit network; offset times; scheduling; transfers

1. Introduction

Bus transit scheduling is concerned with the day-to-day operations.

It is indeed the most important component that is of concern to the

users and operators. Efficiency of any public transport system could

be increased through proper scheduling. Scheduling is an activity that

essentially involves the assignment of vehicles and crew in an economical

fashion, in response to existent and latent ridership patterns,

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and in accordance with written and unwritten labor rules. A good

schedule minimizes both the waiting times for the passengers as well

as the transfer time from one route to another. In effect it will produce

a better level of service (LOS) to its passengers at no extra cost. In

most of the transit networks it is not always worthwhile to provide a

direct route when there is no adequate demand. Thus some users may

need to make transfer when there are direct routes. This transfer

involves not only waiting but in general causes inconvenience to the

users particularly during bad weather conditions. Any transit user,

who missed a transfer on a rainy day by few seconds knows the

importance