Green light optimal speed advisory

The goal of the GLOSA (Green Light Optimal Speed Advisory) service is to predict the green phases of the traffic lights as
well as to provide the drivers the information, if they can pass
the traffic light within the present green phase.


The two main applications are the Green-Wave- and the Deceleration Assistant:

  • Green-Wave-Assistant: The assistant shows
    information which enable to reach the green phase at
    the next signal-controlled junction. Thus, unnecessary stopping and acceleration procedures can be prevented.
  • Deceleration Assistant: The driver will be informed that he cannot reach the green phase at the next signal-controlled junction. He can roll out the vehicle to prevent unnecessary brake and acceleration procedures.

In the C-ROADS project, there are two ways to get the GLOSA service into the vehicles:

  • via ETSI G5 directly into the on-board computer of the vehicle
  • via mobile network into a smartphone app

With help of this two applications, the driver can adapt his driving behaviour according to the information and thereby the efficiency and driving comfort can be increased.



  • Zero accidents at junctions with traffic lights


  • Harmonised brake and acceleration procedures
  • Small consumption and thus a more comfortable driving for the road users

Environmental issues

  • Reduction of pollutant emissions
  • Reduction of noise emissions

Implemented by