What is C-ITS?

C-ITS stands for Cooperative Intelligent Transport Systems: vehicles and infrastructure communicate with one another.

Typical C-ITS participants are:

Stationary RSUs - Road Side Units

  1. Traffic lights (traffic signal installations)
  2. Roadworks signs
  3. Toll gantries on motorways

Vehicles, OBUs (On-Board Units)

  1. Trams
  2. Buses
  3. Cars
  4. Emergency vehicles

C-ITS packets are transmitted on 5.9 GHz. The packets are unencrypted, but they can be signed.

An overview of which vehicles and infrastructure actually send C-ITS: Who is sending C-ITS?

C-ITS Messages

Various types of messages are sent via C-ITS.

The most important ones are:

Message Type Meaning
CAM Cooperative Awareness Message: periodic status message sent by vehicles
DENM Warning about exceptional situations, e.g. roadworks, traffic jams, stationary vehicles
MAPEM Description of intersections, lane geometry
SPATEM Signal states and timings of traffic lights
IVIM Road signs, infrastructure information