Traffic segment

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Versions

1.0 (current)
0.9
History

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Drafts

This is a draft. It may be included in Open511 in the future, but is not currently a maintained part of the specification. If you're interested in using it or participating in its development, please get in touch.

Overview

purpose	Traffic-speed data for a road segment
method	GET

Parameters

This resource supports the bbox, geography, tolerance, jurisdiction, updated, road, and area filters with the same semantics as in Event. Field selection is likely to be particular useful on this resource, as clients may want to regularly fetch current speeds without re-downloading geospatial data. Some URL parameters are common to all resources: format, version, accept-language, and limit.

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<open511
    xml:lang="en"
    xml:base="http://my.city.gov/api/"
    xmlns:gml="http://www.opengis.net/gml"
    version="v1"
>
  <traffic_segments>  
    <traffic_segment>
        <link rel="self" href="/api/traffic_segments/my.city.gov/52" />
        <link rel="jurisdiction" href="/api/jurisdiction/my.city.gov" />
        <id>my.city.gov/52</id>
        <updated>2013-10-22T15:45:00Z</updated>
        <roads>
            <road>
                <link rel="self" href="/api/roads/my.city.gov/highway-2" />
                <name>Highway 2</name>
                <direction>N</direction>
                <from>Exit 10</from>
                <to>Exit 12</to>
            </road>
        </roads>
        <geography>
          <gml:LineString srsName="urn:ogc:def:crs:EPSG::4326">
            <gml:posList>47.33 -71.17 47.36 -71.15 47.35 -71.1 47.4 -71.2</gml:posList>
          </gml:LineString>
        </geography>
        <current_speed>30</current_speed>
        <current_travel_time>333</current_travel_time>
        <historical_speed>40</historical_speed>
        <historical_travel_time>250</historical_travel_time>
        <link rel="historical_traffic_conditions" href="/api/traffic_segments/my.city.gov/52/historical_conditions" />
        <areas>
            <area>
                <link rel="self" href="http://geonames.org/6076945/about.rdf" />
                <id>geonames.org/6076945</id>
                <name>Monte Creek</name>
            </area>
        </areas>
    </traffic_segment>
  </traffic_segments>
  <pagination>
    <offset>0</offset>
  </pagination> 
</open511>

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{
    "traffic_segments": [
        {
            "id": "my.city.gov/52", 
            "updated": "2013-10-22T15:45:00Z", 
            "jurisdiction_url": "/api/jurisdiction/my.city.gov", 
            "url": "/api/traffic_segments/my.city.gov/52", 
            "current_travel_time": 333, 
            "current_speed": 30,
            "historical_speed": 40,
            "historical_travel_time": 250, 
            "historical_traffic_conditions_url": "/api/traffic_segments/my.city.gov/52/historical_conditions", 
            "roads": [
                {
                    "url": "/api/roads/my.city.gov/highway-2", 
                    "to": "Exit 12", 
                    "direction": "N", 
                    "from": "Exit 10", 
                    "name": "Highway 2"
                }
            ], 
            "geography": {
                "type": "LineString", 
                "coordinates": [
                    [
                        -71.17, 
                        47.33
                    ], 
                    [
                        -71.15, 
                        47.36
                    ], 
                    [
                        -71.1, 
                        47.35
                    ], 
                    [
                        -71.2, 
                        47.4
                    ]
                ]
            },
            "areas": [
                {
                    "url": "http://geonames.org/6076945/", 
                    "id": "geonames.org/6076945", 
                    "name": "Monte Creek"
                }
            ]
        }
    ], 
    "pagination": {
        "offset": 0
    }, 
    "meta": {
        "version": "v1"
    }
}

Traffic segment data structure

Field	Type	Description
id	Open511 ID	*Mandatory* A globally unique ID for the traffic segment, following the Open511 ID format.
self	Link	*Mandatory* Self link to the current resource.
jurisdiction	Link	*Mandatory* Link to the jurisdiction publishing the traffic segment.
updated	DateTime	*Mandatory* When the content of the resource last changed. More specifically, must be the time at which the current version of this resource first became available via this Open511 API. Clients are likely to poll for changes via requests like `?updated=>2013-10-01T15:10Z` where the timestamp is the last time they made such a request. Because of this, implementors need to be certain that the resource version with an `updated` field of `2013-10-01T15:10Z` was indeed accessible to API requests at that time.
geography	Geospatial	*Mandatory* Geographical coordinates for this segment. May be Point or LineString. If LineString, coordinates must be ordered properly in the direction of the road.
roads	Collection of road elements	*Mandatory* Roads to which this segment belongs. Usually a segment belongs to a single road, but the format supports multiple roads for cases where, for example, a single physical stretch of road is considered part of multiple numbered highways.
current_speed	Integer	*Mandatory* The speed of traffic, as of the time in `updated`. In km, unless the jurisdiction has set a `distance_unit` of MILES.
current_travel_time	Integer	Optional The time, in seconds, to drive through this segment. (Only makes sense if `geography` is a LineString.)
historical_speed	Integer	Optional The usual speed for this segment at this time of the day; the exact semantics of how this number is calculated may differ between jurisdictions.
historical_travel_time	Integer	Optional The usual time, in seconds, to drive through this segment at this time of the day.
historical_traffic_conditions	Link	Optional A link to a list of historical traffic condition resources for this segment.
name	Free text	Optional A descriptive name for the road segment.
areas	Collections of area elements	Optional Areas within which this segment falls.

Road structure

Field	Type	Description
name	Free text	*Mandatory* Name of the road affected by the event; should be the same as in the linked Road resource.
self / url	Link	*Mandatory* Link to the Road resource for this road.
direction	Enum	*Mandatory* Direction of this segment. Value list: - N - NW - W - SW - S - SE - E - NE
from	Free text	*Optional (mandatory if `to` is provided)* A description of the point on the road where the segment begins -- for example, the name of an intersecting road, or an exit number. If no `to` field is provided, this field means "nearby".
to	Free text	Optional A description of the point on the road where the segment ends.