An estimate of the added fuel consumption caused by poorly maintained roads in Malta

Abstract

Road roughness - a general term used to describe the deviation or elevation of the road's surface from a true planar surface - is known to increase fuel consumption by virtue of the additional rolling resistance to motion imposed on motor vehicles. Given the complete reliance on roads for land transport in Malta, knowledge of the extent to which rough roads impact fuel consumption should be of interest. Yet, no evidence was found that this matter has been tackled to date. The aim of this study is, then, to attempt to quantify how much of the current fuel consumed by road vehicles in Malta can be attributed to the poor state of the roads. In order to arrive at the required figure, an inexpensive measuring method is developed to measure road roughness and express it in terms of a standard road roughness metric known as the International Roughness Index (IRI). Subsequently this method is applied to survey the state of a representative portion of the Maltese road network. Data from the survey is combined with a mechanistic model that simulates the various forces on a vehicle, including the resistance due to road roughness, during a number of typical trips on Maltese roads under local traffic conditions. The outcome of the simulation indicates that 4.8% of fuel consumed by road vehicles in Malta can be attributed to excessive road roughness that results from poorly maintained roads.