Road Network Events

4 minute read

The following events handle the creation and modification of the road network within the simulation. The road network consists of intersections (nodes) and roads (edges) that form the topology on which vehicles travel. These events are emitted during runtime when properties of roads or intersections change.

During initialization, the complete road network can also be downloaded via the simulation’s REST endpoint at /simulation/road-network/intersections and /simulation/road-network/roads. This is particularly useful for the visualization to render the full road network at startup. For details on the structure, refer to the tutorial on the road network.

road-network:intersections-added

Informs all participants that new intersections have been added to the road network. Each intersection represents a node in the road network and is defined by a unique identifier and a geographic position.

Important

This event is not used in the competition setting.

Senders

  • SIMULATION

Receivers

  • OPTIMIZER
  • SIMULATION
  • VISUALIZATION

Data Fields

Field Type Required Description
intersections array Yes A list of intersection objects that were added.

Each intersection object contains:

Field Type Required Description
id integer Yes The unique identifier of the intersection.
latitude number Yes The geographic latitude of the intersection.
longitude number Yes The geographic longitude of the intersection.

Example

{
  "category": "road-network",
  "name": "intersections-added",
  "data": {
    "intersections": [
      { "id": 0, "latitude": 49.87318, "longitude": 8.65148 },
      { "id": 1, "latitude": 49.87291, "longitude": 8.65026 },
      { "id": 2, "latitude": 49.87244, "longitude": 8.6484 }
    ]
  }
}

Flow after Triggering

All receivers register the new intersections in their internal representation of the road network.

road-network:roads-added

Informs all participants that new roads have been added to the road network. Each road represents a directed edge connecting two intersections, along with properties such as length, and maximum speed.

Important

This event is not used in the competition setting.

Senders

  • SIMULATION

Receivers

  • OPTIMIZER
  • SIMULATION
  • VISUALIZATION

Data Fields

Field Type Required Description
roads array Yes A list of road objects that were added.

Each road object contains:

Field Type Required Description
id integer Yes The unique identifier of the road.
from integer Yes The identifier of the intersection where the road starts.
to integer Yes The identifier of the intersection where the road ends.
length number Yes The length of the road in meters.
maximum-speed number Yes The maximum allowed speed on the road in km/h.

Example

{
  "category": "road-network",
  "name": "roads-added",
  "data": {
    "roads": [
      { "id": 0, "from": 0, "to": 1, "length": 100.0, "maximum-speed": 50 },
      { "id": 1, "from": 1, "to": 2, "length": 150.0, "maximum-speed": 30 }
    ]
  }
}

Flow after Triggering

All receivers register the new roads in their internal representation of the road network.

road-network:changed-road-property

Informs all participants that a property of an existing road has been changed. This event can be emitted during runtime, for example when the simulation adjusts road parameters such as the maximum speed to simulate traffic jams.

Senders

  • SIMULATION

Receivers

  • OPTIMIZER
  • SIMULATION
  • VISUALIZATION

Data Fields

Field Type Required Description
road-id integer Yes The unique identifier of the road whose property changed.
properties object Yes An object containing the changed properties and their new values.

Known properties:

Property Type Description
maximum-speed number The new maximum allowed speed in km/h.

Example

{
  "category": "road-network",
  "name": "changed-road-property",
  "data": {
    "road-id": 1,
    "properties": {
      "maximum-speed": 30
    }
  }
}

Flow after Triggering

All receivers update the specified property of the given road in their internal representation.

road-network:changed-intersection-property

Informs all participants that a property of an existing intersection has been changed. This event can be emitted during runtime when intersection parameters are modified.

Important

This event is not used in the competition setting.

Senders

  • SIMULATION

Receivers

  • OPTIMIZER,
  • SIMULATION,
  • VISUALIZATION

Data Fields

Field Type Required Description
intersection-id integer Yes The unique identifier of the intersection whose property changed.
properties object Yes An object containing the changed properties and their new values.

Example

{
  "category": "road-network",
  "name": "changed-intersection-property",
  "data": {
    "intersection-id": 0,
    "properties": {}
  }
}

Flow after Triggering

  1. All receivers update the specified property of the given intersection in their internal representation.
  2. The visualization may update the visual representation of the affected intersection.

Updated: