ESTIMATION OF LANE DISTRIBUTION OF TRUCK TRAFFIC FOR PAVEMENT DESIGN

For structural analysis of pavement design and pavement evaluation, th ere is often a need to compute critical-lane traffic loading from dire ctional traffic-volume input. The accurate estimation of the lane dist ribution of truck traffic is an important element in this process. Thi s paper presents a project conducted in Singapore to study the lane-di stribution characteristics of truck traffic in five different road cla sses. The effects on the lane distribution of trucks by the following four factors are presented: the functional class of the road, the numb er of traffic lanes, the total directional traffic volume, and the vol ume of truck traffic. Statistical regression models for estimating tru ck volume in the critical lane were established for hourly traffic-vol ume input and daily traffic-volume input, respectively. A comparison w ith three widely used procedures indicated that the proposed regressio n approach produced the best results. It is proposed that highway agen cies adopt the approach and develop their own regression models to pro vide accurate lane traffic-loading input for pavement design, pavement monitoring, and pavement evaluation.