Platoon-Based Impact Assessment of Heavy-Duty Vehicles on Traffic Stream Characteristics of Highway Lanes Under Mixed Traffic Environment

Heavy-Duty Vehicles (HDVs) on highways are among the major passengers and freight traffic carriers that occupy any space available on the roadway. The movement of HDVs under the mixed traffic environment causes higher levels of interaction between vehicles due to their physical and operational characteristics. Besides, the HDVs operating at less than their desired speed on the highway lanes cause a mixed traffic platoon formation. The primary purpose of the study is to investigate the impact of multi-class HDVs on the speed and flow rates of each highway lane under platooning conditions. In this study, traffic data was collected using an Infra-Red (IR) sensor-based device at six highway sections in India. The simultaneous equations approach is used to model the traffic speeds for determining the Dynamic Passenger Car Unit (DPCU). The speed-flow plots are established for Median Lane (ML) and Kerb Lane (KL), a minute before the arrival of HDVs (state A) and a minute after the arrival of HDVs (state B) at the IR sensor detection point, to quantify the impacts of HDVs on the speed and traffic flow rate. The study findings reveal that the speed and flow in ML and KL reduce significantly due to the influence of multi-class HDVs in the general traffic mix. Also, the speed and flow rate in ML and KL decreased with an increase in the percentage of multi-class HDVs. However, this effect was found to be comparatively higher in the ML than that in the KL. Finally, this study sets out recommendations to mitigate the adverse impacts of multi-class HDVs on the highways to enhance the speed and flow rate.