cooperative awareness message (C2C) (CAM)
Cooperative Awareness Messages(CAM) are information exchanged between vehicles and infrastructure components in road traffic. Communication takes place either via the WLAN-basedDSRC system or via Cellular V2X( C-V2X) mobile communications technology.
CAM messages are status information about traffic flow, vehicle position, driving speed, driving direction, vehicle status and much more, which is exchanged between vehicles using car-to-car communication( C2C) or via roadside units ( RSU) using car-to-infrastructure communication( C2I) and the traffic control center. CAM messages are sent out once per second.
CAM information provides information about the flowing traffic. They are compressed and transmitted to the traffic control center. They contain vehicle data, date with time, position and speed. By aggregating these data, average values for speed, waiting time or number of stops are calculated. They can also be used to control traffic lights according to traffic conditions.
CAM messages are used, for example, for automated calls to the eCallemergency call system. Other messages are sent as Basic Safety Messages( BSM) and Decentralized Environmental Notification Messages( DENM).