Analysis of the Macroscopic Relations for No-Lane Based Heterogeneous Traffic Stream

Speed-density relations play a major role in dynamic macroscopic modeling. These relations are also used for estimating the other important macroscopic relations. This paper makes an attempt to understand the effect of field data collection procedures on the estimated model parameters. The issues in getting appropriate speed-density data with respect to heterogeneous traffic stream are discussed using the field observations. Greenshields linear speed-density model has been utilized for understanding the issues related to the parameter estimation. From the results, the jam density corresponding to the speed-density model estimated based on the data obtained using conventional methodologies is way lower than the jam density that can be accommodated by the road section. An approach proposed by Cassidy for identifying suitable observation periods was found to be useful in getting a relatively better speed-density model.