ATMS02-Traffic Probe Surveillance Transaction Set Diagram



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The following discusses how the National ITS Architecture provides the transportation service described by this service package. Each numbered item describes the operation of that portion of the service package identified with the corresponding number on the transaction set diagram.

  1. There are several different approaches to traffic probe surveillance that are covered by this market package, ranging from probe applications that use basic vehicle transponders to applications that collect a richer set of data from intelligent probe vehicles using several different wireless communications options. Increasingly intelligent vehicles know their current location (position fix) and have access to travel data such as current vehicle speed and heading and a recent history of stops and starts that can be used to measure current traffic conditions.

  2. Vehicles communicate with short range communications equipment in the Roadway Subsystem as they pass through the road network. Information is collected by the Roadway Subsystem (traffic probe data), which includes different information depending on implementation approach and passing vehicle equipment.

    • Vehicles that are equipped with only a transponder provide a unique identifier (traffic probe data) as they pass a network of beacons that track the progress of vehicles through the traffic network. The system implements measures to ensure that the privacy of individual vehicles and drivers is preserved.

    • In more advanced implementations, intelligent vehicles report their current position, speed, heading and snapshots of events including starts and stops, speed changes, and other information (traffic probe data) that can be used to measure traffic conditions.

    The short range communications equipment forwards the collected probe data (traffic probe data) to a center that collects, processes, uses, and distributes the collected probe data. The center may be an Information Service Provider or Traffic Management Subsystem since traffic probe data supports both traffic operations and traveler information services. Map update providers also collect and use advanced traffic probe data to verify and improve the accuracy of their maps.

  3. The Information Service Provider can also receive traffic probe data directly from subscriber vehicles using wide area wireless communications. The Information Service Provider can aggregate the information from all of its subscriber vehicles to determine information about the road network.

  4. It is also possible to use vehicles on toll roads as probes. The Toll Administration Subsystem can provide the Traffic Management Subsystem and/or an Information Service Provider with toll probe data that is gleaned from transponder communications that support toll road operations.

  5. Transit fleets are another potential source for traffic probe data. The Transit Management Subsystem tracks the performance of its transit vehicles and can provide the Traffic Management Subsystem and/or an Information Service Provider with probe information from the transit fleet (transit probe data).

  6. The Traffic Management Subsystem and Information Service Provider share probe information. The Information Service Provide provides road network traffic probe data to the Traffic Management Subsystem which can use it to determine travel times, speeds, etc. about the roadway. The Traffic Management Subsystem can analyze and reduce any collected probe information to determine current and expected traffic conditions. The Traffic Management Subsystem may share the raw data or the aggregated information (road network conditions) with an Information Service Provider.