Provide in vehicle speed advice based on the signal phase and timing of the approaching traffic light

Optimal Speed Advice at intersections has been a good use case for a long time, and many solutions have existed for a while. However, these solutions lack the feasibility and openness needed for large-scale deployments. Monotch’s solution changed the status quo and implemented this use-case nationally in The Netherlands and proof of concepts in Norway, Denmark, and Belgium.

How green light optimal speed advice (GLOSA) works

When vehicles are on the road, their positional data (CAM messages) collected by the service providers of the OBU/ APP is forwarded to traffic light controllers on route via TLEX. In return, the traffic light controllers send back signal phase and timing information of the approaching intersections to the service providers via TLEX. Service providers can then use this information to generate vehicle speed advice. This is an open ecosystem solution using cellular communication.

Benefits to optimise traffic flow

The proven benefits of this use case include a substantial reduction in waiting time, fuel consumption and emissions. The smoother traffic flow improves the efficiency and safe passage of vehicles crossing intersections, reducing the number of stops at intersections and enabling a faster start at green lights. Monotch’s open-ecosystem solution is also a cost-efficient alternative to expensive VMS signs, e.g. ‘Green wave’, to deliver comparable benefits.

Impact on the environment

The Green Light Optimal Speed Advice at intersections use-case shows how we can positively impact the environment through real-time traffic data exchange.

  • 3% fuel reduction when approaching an intersection
  • 5% reduction in CO emissions
  • 2% reduction in HC emissions
  • 2% reduction in NOx emissions


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