A system and method for controlling a host vehicle in a platoon of vehicles are disclosed. The method includes receiving speed data of a leading vehicle from the leading vehicle via a vehicle communication network, and receiving speed data of a preceding vehicle from a sensor system of the host vehicle. The preceding vehicle is positioned immediately ahead of the host vehicle. The leading vehicleis positioned ahead of the host vehicle and the preceding vehicle. The method includes calculating a transfer function between the leading vehicle and the host vehicle and determining a string stability level of the platoon of vehicles based on the transfer function. The string stability level indicates a speed variation of the platoon of vehicles. Further, the method includes calculating a traffic congestion level based on the string stability level, and controlling a vehicle system of the host vehicle based on the traffic congestion level.