Development of speed-flow relationship for heterogeneous traffic using computer simulation

Road traffic in India, is heterogeneous, and is characterized by the presence of vehicles with wide ranging static and dynamic characteristics. Generally, all these vehicles use the same road space without any segregation and this results in a variety of traffic mix, flows and densities over time and space. In this study, a newly developed heterogeneous traffic flow simulation model (HETEROSIM) has been used to develop, a set of speed-flow curves for traffic on road spaces of widths 7.5m, 11.0m and 14.5m (equivalent to two, three and four lanes). The developed speed-flow relationships are found to follow the standard pattern indicating the goodness of the model. These curves will be useful, in addition to estimate the capacity of the roads, to predict the traffic speed on divided roads for a given traffic volume over a wide range, which is an important input for planning of road networks and road traffic operations.