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UC 11: Traffic jam ahead warning

Operation use case​

Purpose

Informing and warning road users about traffic jams and more importantly, the traffic jam tail, which they are approaching on their route.
Provided timely and adequate notifications, road users can anticipate the traffic jam by reducing their speed in time and gradually and safely reducing the traffic jam. In this way, incidents can be avoided and general road safety improves.

Position of road users

Road users receive information about the location of the traffic jam on their route. Road users who come close to the traffic jam cake (and drive in the same direction of travel) will receive a notification so that they can adjust their driving behaviour. The location and distance to the traffic jam are shared with the road user.

Upstream

The vehicle, upstream of the traffic jam (red vehicle in figure), receives a notification of traffic jams on its route and is informed about the location and distance to the traffic jam.

In traffic jams

The traffic jams will be shown on the map (as a line string, the blue -awareness zone- and orange -history zone- line in the figure) so that the end user has an overview of the length of the traffic jam.

Downstream

The road user (blue vehicle in lower right in figure) has already passed the traffic jam. No more reporting needs to be given.

Data sources​

The main sources for these reports are:

  • Be-Mobile traffic jam information

MI & Historical archive​

DENM information​

Based on the eventHistory trace and eventSpeed, the enduser client can calculate the duration of the delay.

Cause and sub cause codes are:

CausecodeDescriptionSubcausecodeDescription
1trafficCondition0unavailable
2Traffic jam slowly increasing
3Traffic jam increasing
4Traffic jam strongly increasing
5Traffic stationary
6Traffic jam slightly decreasing
7Traffic jam decreasing
8Traffic jam strongly decreasing

MI headers​

{
  "messageType": "DENM",
  "originatingCountry": "BE",
  "protocolVersion": "DENM:1.3.1",
  "publisherId": "BE00004",
  "publicationId": "BE00004:DENM_TRAFFIC_JAMS_01",
  "custom-mobilidata-publisherType": "PIP",
  "custom-mobilidata-dtapEnvironment": "production",
  "custom-mobilidata-useCase": [11],
  "quadTree": [
  ]
}

Historical archive​

As well the original messages as the RUF messages ar stored in the historial database.

Data Processing (PIP)​

Create an event​

The information from the above-mentioned sources is collected and validated in the PIP. Then, the "traffic jam warning" events are published on the MI as DENM messages.

Be-Mobile traffic jam information

The Be-Mobile traffic jam information is the main source of notifications for this use case. Our traffic jam information is based on Floating Car Data from a representative fleet of cars and trucks, and works as follows:

  • GPS positions map matching on a map
  • Quality control at each individual GPS point: filtering out bad, irregular GPS data.
  • Aggregate GPS positions over time per segment.
  • Calculate travel times on the entire road network by segment, each segment is up to 50 meters long to deliver high degree of granularity.
  • Detecting traffic jams: every 20 seconds an output is generated from all segments where a traffic jam has been formed, adjacent segments are connected into one traffic jam.
    • The traffic jams and traffic jam messages are only generated on connecting roads (OSM classification: motorway, trunk, primary, secondary, tertiary), not on access roads (OSM classification: unknown, residential).

The Be-Mobile traffic jam information is used by the PIP to generate traffic jam notifications on the first segment (in the direction of travel) of each traffic jam. Every 20 seconds, the PIP processes the new list of traffic jam segments and creates new traffic jam tail notifications or updates existing traffic jam tail messages (DENM messages).

Follow-up and cancellation of the event​

Every 20 seconds, the PIP processes a new update from traffic jam segments to traffic jam events. Existing traffic jams are updated, new events are created for new traffic jams and if traffic jams disappear, the events are immediately cancelled.

Quality Control​

The traffic jam notifications from Be-Mobile are the result of an advanced algorithm with extensive quality control and validation.

In addition, the PIP will perform a quality check on the DENM messages, before publishing them on the MI, the following checks will be implemented:

  • Technical validation
    • Are the protocols respected? Incorrect messages are filtered out.
    • Are all required fields filled in according to C-roads standard? Incomplete DENM messages are filtered out.
    • Is the format correct? Messages in incorrect format will not be used.
    • Isn't the message too old? Outdated messages are filtered out. Several checks are done in the PIP to check that a message sent to the MI is not outdated. For example, if a newer update is already in the PIP before the previous message has been sent to the MI (e.g. due to a delay in the PIP). It is not possible to put an exact time on 'outdated messages', as this time will be use case and source dependent.

RUF​

RUF is not used in this use case.

RUF will rarely, if ever, achieve the same level of detail and reliability within a time span of 20 seconds as the traffic jam information based on FCD. RUF would only cause noise in addition to the accurate and frequency of traffic jam (tail) updates.

MI & Historical Archive​

The following data streams run over the MI and are archived after conversion:

  • DENM

    • DENM implementation such as use-case HLN-TJA (Traffic Jam Ahead) in C-ROADS 2.0

      • causeCode 1 (traffic condition)

        • subCauseCode 0

Service Provider Implementation​

N/A

Message example​

UC 11 Message Example
{
    "shardId": "1",
    "latitude": "51.155076",
    "quadTree": ",120202132001132311,1202021320011,1202021320013,",
    "causeCode": "1",
    "longitude": "4.382742",
    "shardCount": "1",
    "messageType": "DENM",
    "publisherId": "BE00004",
    "subCauseCode": "3",
    "publicationId": "BE00004:DENM_TRAFFIC_JAMS_02",
    "baselineVersion": "2.1.0",
    "protocolVersion": "DENM:1.3.1",
    "originatingCountry": "BE",
    "custom-mobilidata-useCase": ",11,",
    "custom-mobilidata-timestamp": "1737369968058",
    "custom-mobilidata-alertCCodes": "72",
    "custom-mobilidata-publisherType": "PIP",
    "custom-mobilidata-baselineVersion": "1.0.0",
    "custom-mobilidata-dtapEnvironment": "production"
}
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Last updated on by taeyma41