Overtaking behaviour of vehicles on undivided roads under mixed traffic conditions

Abstract

Overtaking is one of the most complex and important manoeuvre on undivided roads where the vehicles use the opposing lane to overtake the slower vehicles with the presence of oncoming vehicles from opposite direction. This process involves lane-change manoeuvres, acceleration and deceleration actions and estimation of relative speed of overtaking and overtaken vehicles, and also, estimation of speed and distance of the oncoming vehicle. Traffic on Indian roads is highly mixed in nature with widely varying static and dynamic characteristics of vehicles. These vehicles do not follow strict lane discipline and occupy any available lateral position on the road space. In the present study, details of overtaking data is collected on a two-lane two-way rural road using moving car observer method and registration plate method and overtaking characteristics of all types of vehicles under mixed traffic conditions are observed and mathematically modelled. Two types of overtaking strategies are observed in the field such as flying and overtaking. Graphs are plotted between the relative speed of the overtaking and overtaken vehicles against the overtaking time and negative correlation is found between the speed differential for all categories of vehicles and the total overtaking time. It was found the increase in flow rate causes an increase in demand of passing and decrease in passing supply.