Multilane highways encompass a variety of commercial vehicles based on size, shape, class, and maneuvering ability. The mixed traffic flow of commercial vehicles with different operating capabilities results in variation in speed, flow, and density parameters in traffic. The aim of this research is to understand the real traffic behavior of different commercial vehicles on multilane highways under platooning conditions. For this purpose, traffic data was gathered on the highways using an infra-red sensor. Macroscopic traffic relationship diagrams were developed under two different traffic regimes with two different classes of commercial vehicles as platoon leaders. The results of the traffic regime-based comparative analysis demonstrated that commercial vehicles as different platoon leaders had a significant influence on traffic speed, flow, and density, resulting in reduced highway capacity. This study may be helpful to highway engineers and traffic analysts to evaluate and plan improvements in traffic facilities for better operation of highways.