EFFECT OF TRUCK LOAD VARIATIONS ON ROAD PERFORMANCE AND OPTIMUM LIMIT OF TRUCK FACTOR

Abstract

Overloading by commercial trucks in Pakistan is considered to be a serious problem. In the past, some axle load surveys were carried out in the country to gauge the extent of overloading. As a consequence of these surveys, the damaging effects of the heavy loaded vehicles on the pavement have been appreciated and some legal axle load limits were enacted in the country. Without fully examining the overall economic impacts of these limits on the road freight industry the limits could never be implemented and enforced in a true sense. In the present study axle load data had been studied through ANOVA and generate a regression model between truck factor (EALF) and gross vehicular weight (GVW). The highway development and management (HDM-4) software package has been used for economical analysis in order quantify the impacts of different axle loads of various types of trucks according to the axle configuration on the total transport costs which include both road user costs and agency costs. The analysis has been carried out not only for the present situation but observe the long term (20 years) effects of axle load limits and truck factor (EALF) on the total transport costs. The optimal EALF and axle load limits were calculated for various axle types of truck. These limits are a little higher than the existing limits but it is hoped that these will be implementable and will not drastically reduce the profitability of the truck owner / operators. It has been concluded that the optimal EALF and axle load limits would be beneficial for the economy of the country as it gives 4.86% saving in the total transport cost.