Green Light Optimal Speed Advice (GLOSA) Demo / Use Case

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Demonstration scenario

This demonstrator gave speed advice (GLOSA) to a specific vehicle in a traffic simulator (SUMO). The speed advice information was acquired from the traffic light controller on the current signal group status and the planned state changes. Planned state change information was not a standard feature available on every traffic light controller. Therefore, the traffic adaptive control algorithm Imflow was often used for this, as it plans the optimal control plan up to 1 minute ahead. Communication between the RSU, which calculates the speed advice, and the vehicle took place through 2 paths, 802.11p and connected (over the internet, for example through 3G or UMTS). Normally, the vehicle is driving on the street and has its own GPS location measurement from a smart phone or tablet. However, for this indoor demo, simulation software took over this function. Therefore, a physical connection between the tablet and the demo laptop was required to pass this simulated GPS information.
In the demonstration scenario the stand visitor saw the screen following a pink limousine driving on a simulated road running in the SUMO program. The limousine approached an intersection and depending on the signal plan 3 scenarios were possible:

  1. It will take too long before the traffic light turns green to give a useful speed advice. An advice lower than 30 km/h is not efficient, safe and comfortable for the driver. Therefore an icon for no green wave will be shown on the screen.
  2. The light will turn green after the vehicle would normally arrive, but not too long afterwards. In this case an advice between 30 and 45 km/h is given, the driver can slow down and will not have to stop following the advice.
  3. The light will turn green soon, the driver should keep at the speed limit of 50 km/h to make the green light and help efficient traffic flow.

For the 2nd scenario, the simulator adjusted the speed of the limousine so the stand visitor could see that the vehicle really doesn’t have to stop.

As previously described cabling was necessary to simulate the GPS location. The figure below shows a connection between the central Ethernet switch and the OBU, which normally isn’t there. This is to give the simulated GPS locations to the OBU.

Cable connections

The tablet required a manual startup of the MOBiAGENT app, followed by the GLOSA app. The GLOSA app stayed running on the screen to display the speed advice, but the MOBiAGENT was required to receive the messages through the internet.
The laptop came with a standard windows installation, there was an icon on the desktop called “MOBiNET Demo.jar” which had to be double clicked to start up the simulation part of the demo. In SUMO the screen could be panned by clicking anywhere in the map, zooming in and out is done by the scroll wheel.

Select “real world” from this drop down list to boost graphics

Stop the simulation and track the vehicle

As a next step the simulation followed the cooperative vehicle, this vehicle drove from the west of the map towards the intersection. Shortly after the intersection its position was reset to the west side of the map again. It stood out from the other yellow vehicles as it was a pink limousine.

Added value MOBiNET

The MOBiNET platform offers special features for connected communication with the Communication Agent (CA, central) and Communication Manager (CM, in the vehicle). These components together keep track where the MOBiNET vehicles are and only send messages to them relevant to their location. This way the RSU only has to post the data to the CA with a location reference and it will be delivered to the right vehicles by MOBiNET. This connected data path through the CA and CM has been used for the demonstrator.

User feedback / validation

The feedback was mostly limited to the differences in symbols and traffic signs in different countries. The common blue sign with white numbers to indicate an advisory speed is well-known in the Netherlands, Belgium, and Germany, but unknown in other countries. In Sweden a blue sign with a white number even represents a mandatory speed limit.

There was positive feedback about the application and the live integration with a traffic controller at the demo.