DISCHARGE CHARACTERISTICS OF HETEROGENEOUS TRAFFIC AT SIGNALIZED INTERSECTIONS

Abstract

The discharge characteristics of heterogeneous traffic, with a wide variation in vehicle characteristics, are significantly different from homogeneous traffic. In this paper, the speed at which heterogeneous vehicles move through the intersection area is analyzed in detail for four different motorized vehicle types -- two-wheelers (motorcycles and scooters), three-wheelers (autorickshaws), cars, and buses. Traffic flow data captured on video are digitally analyzed to determine vehicle positions every second for three intersections in two Indian cities, Baroda and New Delhi. A coordinate conversion procedure is applied to obtain roadway coordinates from screen coordinates, and the speed of the vehicles is determined. The analysis shows that for a given intersection, the speed at which vehicles traverse the intersection space (clearing speed) does not vary significantly by vehicle type. It is expected that such detailed studies of discharge characteristics will help determine methods to estimate capacity at signalized intersections for heterogeneous traffic.