Modeling Platoon Dispersion at Signalized Intersections in Mixed Traffic Scenario

Abstract

Vehicles generally move in the form of platoons after discharging from the stop line of signalized intersection. While moving toward the downstream signal, due to the interaction between moving vehicles, road geometry, traffic composition and their speed difference, platoons get dispersed. Dispersion of platoon influences signal co-ordination, arrival pattern, turning maneuver at upstream signal. Moreover, while designing the intersection under mixed traffic scenario, platoon dispersion is important to create a link between traffic signals. Therefore, the present study is taken up with the objective of estimating the platoon dispersion distance after crossing the stop line. A model is developed based on the simulated data sets. VISSIM, a micro-simulation software, is used to replicate the field traffic conditions. To ensure the applicability of the model in the existing mixed traffic conditions, two different methods were used. Firstly, data were collected from two sites and used for validating the performance of the model. The results indicated a good match (maximum 9% error) between the field-observed and model-estimated platoon dispersion distance. Secondly, the traffic scenario alike the two study sites was created in VISSIM and the simulated and field-observed data sets were compared to check how accurately VISSIM can replicate the existing mixed traffic conditions. It is observed that VISSIM had replicated the field conditions with a maximum error of 10%. Therefore, the output of the study indicates that the proposed model may be used to estimate the platoon dispersion distance with reasonably high accuracy under mixed traffic conditions.