Behavior of traffic composition in Urban Area

The traffic of an urban roads increases rapidly due to the growth in prosperity and vehicle ownership of urban population. The problems occurred due to this increased traffic have also become more and more complex. The urban roads of India generally carry the heterogeneous traffic which is the combination of various vehicles like Cars, Buses, Trucks, Motor cycles, Light goods vehicles, Auto Rickshaws, Pedal Cycles, Hand drawn carts, Animal drawn carts etc. These all vehicles have different speeds, size, Load carrying capacities or passenger capacities etc. which affect the urban heterogeneous traffic flow. The non-uniform carriageway width along the road is common especially in developing countries. Due to change in carriageway width, the traffic stream speed also encounters more congestion level along the length of link. Traffic composition is most important factor which directly affects the traffic stream behavior (i.e., speed, flow and density). In case of homogeneous traffic the characteristics of traffic does not change abruptly, as the traffic composition mainly consisting of same types of vehicle. When the traffic composition has maximum number of two wheelers it gives higher speed value and higher flow values. This is due to the reason that two wheelers occupy less space as compare to car and bus and trucks. Also standstill distance required is very less, as two wheelers can be easily stopped with compare to bus and heavy trucks. Speed is also more when two wheelers are driven on urban streets.