Overtaking process on two lane rural highways

Two-lane roads in India comprise a very large proportion of the road network. Two-lane roads have one lane for use by traffic in each direction and the faster vehicles when approaching slower vehicles, use the opposing lane to overtake the slower vehicles depending on the sight distance available and the gaps in opposing stream. Overtaking involves lane-change manoeuvres, possibly of the acceleration and deceleration actions and estimation of relative speed of the overtaking and overtaken vehicles. Road capacity, level of service and safety are all affected by the passing (overtaking and passing are used in this paper synonymously) ability of faster vehicles. On Indian roads, size, width, speed and operational characteristics vary greatly from vehicle to vehicle. In the present study the decision rules for different types of overtaking are developed. Data collected at three different highways were analysed and the various relationships between relative speed of overtaking and overtaken vehicle and the overtaking time, required gap are also developed.