Data service travel times

Data service travel times

Introduction

The data service travel times contains Minute data of travel times over predefined measurement sites; delivery at the latest 60 seconds after the measurement minute. The travel times contain the current traffic status expressed in travel time between two geographical points on a road. Depending on the provisions of the relevant road authority, the travel time will be a representation of (1) realized travel time, or (2) estimated travel time.

The files are made available as open data on opendata.ndw.nu as traveltime.xml (periodic data with regard to travel times) and measurement_current.xml (configuration data of the measurement sites).

For more information about the structure of the MeasurementSiteTablePublication (measurement_current.xml) you can click here.

Structure and content

General

The data service travel times is part of the real-time traffic data. The specialization (xsi: type) MeasuredDataPublication from PayloadPublication is used for this purpose in the Datex II structure.

The main structure is shown in the figure below.

../../../_images/specialisatie_measureddatapublication.png

In the example below the use of the most important elements in this data service is explained.

Example

The file / soap message with the periodic data of travel times starts with the standard DatexII elements for delivery (see example XML below). The exchange element is used to exchange parameters related to the delivery, in this case the details of the supplier.

Element Explanation
exchange The element is used to exchange data related to the delivery
supplierIdentification describes the sending/delivering party
<d2LogicalModel xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" modelBaseVersion="2" xmlns="http://datex2.eu/schema/2/2_0">
  <exchange>
   <supplierIdentification>
     <country>nl</country>
     <nationalIdentifier>NLNDW</nationalIdentifier>
   </supplierIdentification>
  </exchange>
  <payloadPublication lang="nl" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="MeasuredDataPublication">
    <publicationTime>2017-08-09T08:52:40.008Z</publicationTime>
    <publicationCreator>
      <country>nl</country>
      <nationalIdentifier>NLNDW</nationalIdentifier>
    </publicationCreator>
    <measurementSiteTableReference targetClass="MeasurementSiteTable" version="932" id="NDW01_MT"/>
    <headerInformation>
      <confidentiality>noRestriction</confidentiality>
      <informationStatus>real</informationStatus>
    </headerInformation>
  ..
  </payloadPublication>
</d2LogicalModel>

In the above example, the attribute xsi: type of the PayloadPublication indicates that the specialization “MeasuredDataPublication” has been used. In addition, the following elements were used to provide extra information about the data delivery.

Element Explanation
payloadPublication Element contains the actual delivery of data
publicationTime Date and time the payloadPublication was created
publicationCreator Party that composes the publication
country Country of the composing party
nationalIdentifier Identification composing party
measurementSiteTableReference Reference to the measurementSiteTable
headerInformation Gives status and confidentiality information
confidentiality Confidentiality of the information provided
informationStatus Status of the information supplied

The actual travel time data can be found in the siteMeasurements element (see XML example below). The reference to the measurement location within the measurementSiteTable is done by means of the attributes of the measurementSiteReference element. In addition, the start time of the measurement minute is indicated in measurementTimeDefault.

Warning

The measurementTimeDefault element always indicates the start time of the measurement minute.

Element Explanation
siteMeasurements Contains the measured traffic data
measurementSiteReference Reference to the measurement location included in the measurementSiteTable
measurementTimeDefault Start time of the period (measurement minute) for which measurement data are delivered

<siteMeasurements>
  <measurementSiteReference id="RWS04_T_0258_ID_265" version="1" targetClass="MeasurementSiteRecord"/>
  <measurementTimeDefault>2017-08-09T08:52:00.000Z</measurementTimeDefault>
  <measuredValue index="1" xsi:type="_SiteMeasurementsIndexMeasuredValue">
    <measuredValue xsi:type="MeasuredValue">
      <basicData xsi:type="TravelTimeData">
        <travelTimeType>reconstituted</travelTimeType>
        <travelTime>
          <duration>58.659</duration>
        </travelTime>
      </basicData>
      <measuredValueExtension>
        <measuredValueExtended>
          <basicDataReferenceValue>
            <referenceValueType>staticReferenceValue</referenceValueType>
            <travelTimeData>
              <travelTimeType>reconstituted</travelTimeType>
              <travelTime>
                <duration>51.979</duration>
              </travelTime>
            </travelTimeData>
          </basicDataReferenceValue>
        </measuredValueExtended>
      </measuredValueExtension>
    </measuredValue>
  </measuredValue>
</siteMeasurements>

The measured value and the typing of the value is recorded in the specialization “TravelTimeData” of the element basicData (see also the example above). In the event of a faulty measurement, the dataError subelement is used within basicData to indicate this. About how this is done click here. In addition, the reference value is included within the basicDataReferenceValue element in the measuredValueExtension. A typing of the reference value takes place using the referenceValueType element. In addition, the structure of basicData has been included under travelTimeData to indicate the reference value.

Element Explanation
measuredValue (hoofdelement) Traffic data for a measuring point
measuredValue (subelement) Subelement of measuredValue
basicData The TravelTimeData specialization of basicData contains the basic measurement data
travelTimeType Indication of how the travel time has been determined
travelTime Contains travel time measurement location
dataError The travel time in seconds between two specified locations in the indicated direction
duration The travel time in seconds between two specified locations in the indicated direction
measuredValueExtension Contains information about the reference values
measuredValueExtended Has function to provide reference values at current observation values
basicDataReferenceValue Typing determination of the reference value and status of the traffic
referenceValueType Characterization of the way in which the reference value has been determined
travelTimeData Provides extra information about measurement data (calculation etc.)
travelTimeType Indication of how the travel time has been determined
travelTime Contains travel time measurement location
duration The travel time in seconds between two specified locations in the indicated direction