ABSTRACT
The presence of intersection control in the form of traffic signals create platoons at the exit, which tend to disperse as they progress along the arterial. Among the various fundamental platoon characterizing variables, critical headway is essential for determining whether a vehicle belongs to a platoon or not. This platoon characterizing variable have been studied extensively under homogeneous traffic conditions, but similar studies have not been conducted adequately considering the diversity of traffic and lack of lane discipline exhibited under heterogeneous traffic conditions. The present study identifies the value of critical headway based on the traffic data collected along urban arterials. Data were collected using video graphic survey technique. It was analyzed for each platoon upto 420 m at every 30 m interval. The analyses gave the trend of variation of critical headway on the observed road sections where initial and higher platoon dispersion occurred at downstream of traffic signals. This study enables better understanding of variation of critical headway along downstream of signalized intersections under heterogeneous traffic conditions.
