Variable Message Signs Simulator

The VMS Simulator allows to define variable message signs on top of the existing traffic simulation. An additional application for vehicles allows them to react upon VMS, which can be dynamically controlled.

Installation

Overview

The VMS Simulator extends simulations with variable message signs (VMS), which could by dynamically controlled. A VMS can be placed anywhere along a road and has, amongst others, the following properties:

• Type for different traffic sign semantics,
• Road and lane(s) it corresponds to,
• Visibility as a value telling how well a sign is visible for road users

The concept of a flexible sign type allows testing future traffic signs which are not existent at the moment and also common VMS types like:

• Speed limit signs
• Lane assignment signs (assigns a list of allowed vehicle types to a lane - e.g. Busses, Taxis or even Automated Vehicles)

Any properties of a VMS, beside its position and type, can be changed during the simulation.

In each simulation step the VMS Simulator informs vehicles about any VMS that is inside their sight distance. How vehicles react on VMS can be modeled with the Application Simulator.

Configuration

To enable vehicles to react to VMS in your simulation, your scenario must include the following additional files:

• <scenario-name>/traffic-signs/traffic_signs_config.json: General configuration of the ambassador.
• <scenario-name>/traffic-signs/signs.xml: Detailed configuration of all available variable message signs.
• <scenario-name>/application/TrafficSignsVehicleApp.jar: The jar file which contains the vehicle application to be able to react on VMS.
• <scenario-name>/application/TrafficSignsVehicleApp.json: Configuration for the vehicle application to react on VMS.

Enable VMS Ambassador

To enable the VMS Ambassador in your simulation activate it in <scenario-name>/scenario_config.json:

{
   ...,
    "federates": {
        "application": true,
        "sumo": true,
        "traffic-signs": true
    }
}

Configure the VMS Ambassador

Configuring the Traffic Sign Ambassador in <scenario-name>/traffic-signs/traffic_signs_config.json:

{
    // Name of the XML file which contains the traffic signs
    "signsFilename": "signs.xml",

    // Path to the scenario database
    "database": "../application/<scenario-name>.db"
}

Define VMS

Currently implemented traffic signs:

• Lane Assignment Sign Lanes can be assigned to a specific vehicle type (Bus, Taxi, Autonomous Vehicle,…).
  • Vehicles that are not of the allowed vehicle class will try to change to a different lane as soon as possible.
  • If a Taxi drives on the leftmost lane, but the rightmost is assigned to Taxis only, it tries to change to that lane as soon as possible.
• Speed Limit Signs Speed limits can be set for specific streets or even lanes.
  • Vehicles driving on a lane with a speed limit change their maximum speed (SUMO parameter) to the value the sign specifies.
  • When vehicles change lane they adapt the new speed limit.
  • Vehicles do not prefer faster lanes.

The file <scenario-name>/traffic-signs/signs.xml stores all traffic signs of the scenario.

The following examples show how to define speed limit signs:

<trafficsigns>
    <!-- Speed limit of 130km/h on all lanes of the specified edge. Not variable. -->
    <speedLimit id="speed-limit-sign-1"
                x="51421.50" y="58297.29"
                edge="4822486_685163613_31022629_31022620"
                visibility="1.0"
                variable="false"
                limit="36.1">
    </speedLimit>

    <!-- Three variable speed limit signs for each lane of the edge with different speed limits. -->
    <speedLimit id="speed-limit-sign-2"
                x="51421.50" y="58297.29"
                edge="4822486_685163613_31022629_31022620"
                visibility="1.0"
                variable="true"
                limit="36.1" >
        <lane index="0" limit="27.7" /> <!-- 100km/h on lane 0 -->
        <lane index="1" limit="33.3" /> <!-- 120km/h on lane 1 -->
        <lane index="2" limit="36.1" /> <!-- 130km/h on lane 2 -->
    </speedLimit>
</trafficsigns>

The following examples show how to define lane assignment signs:

<trafficsigns>
    <!-- Variable lane assignment sign that assignes all lanes of the specified edge to all vehicle classes.
            With this sign previous lane assignment signs can be neutraized.
            The sign has also a bad visibility. -->
    <laneAssignment id="lane-assignment-sign-1"
                    x="51419.73" y="58294.31"
                    edge="4822486_685163613_31022629_31022620"
                    visibility="0.3"
                    variable="true"
                    allowedVehicleClasses="ALL" >
    </laneAssignment>

    <!-- Three variable lane assignment signs with different vehicle class assignments per lane. -->
    <laneAssignment id="lane-assignment-sign-2"
                    x="51419.73" y="58294.31"
                    edge="4822486_685163613_31022629_31022620"
                    visibility="1.0"
                    variable="true"
                    allowedVehicleClasses="ALL" >
        <lane index="0" allowedVehicleClasses="Taxi Bus" /> <!-- The rightmost lane is assigned to busses and taxis only. -->
        <lane index="1" allowedVehicleClasses="Taxi" /> <!-- The center lane is assigned to taxis only. -->
        <lane index="2" allowedVehicleClasses="ALL" /> <!-- on the leftmost lane all vehicle types are allowed to drive. -->
    </laneAssignment>
</trafficsigns>

Let Vehicles React on VMS

To equip vehicles with the TrafficSignsVehicleApp you need to add com.dcaiti.mosaic.app.examples.trafficsigns.TrafficSignsVehicleApp to the applications list of the vehicle in the mapping/mapping_config.json.

You can specify the duration after which vehicles shall react on traffic signs by adding the reactionTime parameter (in seconds) to the application in mapping_config.json:

"applications": [
    "com.dcaiti.mosaic.app.examples.trafficsigns.TrafficSignsVehicleApp(10)"
]

You also may want to change the mean sight distance of vehicles and define a deviation for that. You can do this by creating the file application/TrafficSignsVehicleApp.json and edit it as following:

{
    // Mean sight distance of a driver in meters
    "meanSightDistance": 400.0,

    // Max. deviation of sight distance in meters
    "sightDistanceDeviation": 20.0
}

Change VMS During Simulation

With the following code snippets, you can change VMS dynamically during simulation:

long timeToSend = 150 * TIME.SECOND;
String signId = "speed-limit-sign-1"; // As defined in <scenario-name>/trafficsigns/signs.xml
double newSpeedLimit = 13.89; // in m/s
TrafficSignSpeedLimitChange interaction = new TrafficSignSpeedLimitChange(
    timeToSend,
    signId,
    newSpeedLimit
);
getOs().sendInteractionToRti(interaction);

Change variable speed limit sign.

long timeToSend = 160 * TIME.SECOND;
String signId = "lane-assignment-sign-2"; // As defined in <scenario-name>/trafficsigns/signs.xml
int laneIndex = 0;
List<VehicleClass> allowedVehicleClasses = new ArrayList<>();
allowedVehicleClasses.add(VehicleClass.ElectricVehicle);
TrafficSignLaneAssignmentChange interaction = new TrafficSignLaneAssignmentChange(
    timeToSend,
    signId,
    laneIndex, // NOTE: If you don't provide a lane index here, all lanes are assigned to electric vehicles only.
    allowedVehicleClasses
);
getOs().sendInteractionToRti(interaction);

Change variable lane assignment sign. Allow only Electric Vehicles for a specific lane.