Lateral distribution of mixed traffic on two-lane roads

Location of the outer wheel path is an important input in the measurement of deflection response of a pavement and its riding quality. In the simulation of mixed traffic flow, it is also required to assign the position of a vehicle within a lane when it enters the test section. The statistical distributions fitted through the placement data recorded on 19 different sections of two-lane highways in India indicate that the placement of vehicles may follow a unimodal or a bimodal Curve depending upon the percentage of slow and fast moving vehicles. Two parameters are introduced in this technical note. These are placement factor (PF) and skewness range (SR). It is observed that the placement data follow a unimodal curve if PF and SR are less than 1.3 and 0.54, respectively. Otherwise it is a case of bimodality.