1. ¹University of Huddersfield, Huddersfield, UK
2. ²Lancaster University Management School, Lancaster, UK

Correspondence: R Eglese, Department of Management Science, Lancaster University Management School, Lancaster, LA1 4YX, UK

Received October 2008; Accepted August 2009; Published online 14 October 2009.

Abstract

A heuristic algorithm is described for vehicle routing and scheduling problems to minimise the total travel time, where the time required for a vehicle to travel along any road in the network varies according to the time of travel. The variation is caused by congestion that is typically greatest during morning and evening rush hours. The algorithm is used to schedule a fleet of delivery vehicles operating in the South West of the United Kingdom for a sample of days. The results demonstrate how conventional methods that do not take time-varying speeds into account when planning, except for an overall contingency allowance, may still lead to some routes taking too long. The results are analysed to show that in the case study using the proposed approach can lead to savings in CO₂ emissions of about 7%.