AREA OCCUPANCY CHARACTERISTICS OF HETEROGENEOUS TRAFFIC

Abstract

Increasing congestion due to rapid urbanization in developing countries like India necessitates the study of traffic flow for effective traffic management. Most of the traffic studies conducted in this regard were on the lines of methods used in developed countries. These studies were able to represent the traffic behavior only in a very limited manner. In developing countries traffic is composed of several types of vehicles ranging from cars with high speeds to low speed non-motorized vehicles. Microscopic traffic characteristics such as time headway and space headway are difficult to measure due to the heterogeneous nature (no lane discipline, and two or three small vehicles occupying one lane in lateral direction) of the traffic. Even using some of the macroscopic traffic characteristics such as density or occupancy, to study this kind of traffic may lead to erroneous results. Thus it is desirable to have a metric that can represent the heterogeneous nature of traffic in these conditions. Since varying vehicle dimensions are attributed to the lack of lane discipline, a modified measure of occupancy termed as Area occupancy is proposed in this paper. Like occupancy, area occupancy is also measured over time. This measure would also be able to consider the varying vehicle dimensions of the traffic. Based on field observations it is shown that area occupancy is more meaningful in representing the heterogeneous traffic when compared to occupancy.

Keywords:

• Occupancy
• heterogeneous traffic
• passenger car unit