WZDx Specification v4.2

Released February 2023

New Functionality

• Add impacted_cds_curb_zones property to the WorkZoneRoadEvent object to allow indicating if any Curb Data Specification curb zones are impacted by the work zone using new CdsCurbZonesReference object.
• Add work_zone_type property to the WorkZoneRoadEvent object to allow indicating if a work zone road event represents a planned moving operation, an active moving operation, or a standard static work zone.
• Add the following values to the Direction enumerated type:
  • inner-loop
  • outer-loop
• Add velocity_kph property to the FieldDeviceCoreDetails object to allow indicating the velocity of a field device.
• Add work-truck-with-lights-flashing to the MarkedLocationType enumerated type.

Refactoring

No properties were deprecated or removed in WZDx v4.2.

Cleanup

• Expand the description of the geometry property on the RoadEventFeature object to clarify how geometry should be used to represent a road event.
• Update the description of the open and closed enumerations of the LaneStatus enumerated type.
• Update the description of the FlashingBeacon object to clarify that it should only be used as a flashing warning beacon mounted on a temporary traffic control device.

WZDx Specification v4.1

Released September 2022

Changes for the v4.1 release involve new features and cleaning up and redesigning existing functionality without breaking backwards compatibility. Thus, several enumerated type values and object properties were deprecated rather than removed. Most if not all of these deprecated values will be removed in the next major release.

A noteworthy documentation change introduced along with the v4.1 specification changes are that the two feeds that WZDx defines are renamed for clarity:

• Rename the "SwzDeviceFeed" to "DeviceFeed" or "WZDx Device Feed"
• Rename the "WZDxFeed" to "WorkZoneFeed" or "WZDx Work Zone Feed"

New Functionality

• Add is_moving boolean property to the FieldDeviceCoreDetails to allow indicating if any field device is moving as part of a mobile operation.
• Add road_direction property to the FieldDeviceCoreDetails to allow providing the direction of the roadway that a field device is associated with.
• Recommend using Universally Unique Identifiers (UUID) for the id property of the RoadEventFeature, FieldDeviceFeature, and FeedDataSource, noting that a UUID may be required in the next major release.
• Add name property to RoadEventCoreDetails to allow providing a human-friendly name for a road event.
• Add the following values to the MarkedLocationType enumerated type:
  • personal-device
  • ramp-closure
  • road-closure
  • delineator
• Add the following values to the Direction enumerated type:
  • undefined
  • unknown
• Add no-passing to the RestrictionType enumerated type.
• Add a sign_text property to the FlashingBeacon object.
• Add a TrafficSignal object to allow represent temporary traffic signals in a WZDx Device Feed.
• Add two-way-center-turn-lane to the LaneType enumerated type to replace the existing center-left-turn-lane with a more generic value.

Refactoring

• Deprecate is_moving property on the ArrowBoard; use the new is_moving on the FieldDeviceCoreDetails instead.
• Change the conformance of the road_event_id property on the TrafficSensorLaneData from "Required" to "Optional" to allow providing lane-level data without a defined road event.
• Deprecate the road_event_feed_info property on the WorkZoneFeed object; use the new feed_info property instead.
• Add is_start_position_verified and is_end_position_verified boolean properties to the WorkZoneRoadEvent to allow indicating if the start and end positions are verified and clarify what verified means; these properties replace beginning_accuracy and ending_accuracy.
• Deprecate the beginning_accuracy and ending_accuracy properties on the WorkZoneRoadEvent object; use the new is_start_position_verified and is_end_position_verified properties instead.
• Add is_start_date_verified and is_end_date_verified boolean properties to the WorkZoneRoadEvent to allow indicating if the start and end date and times are verified and clarify what verified means; these properties replace start_date_accuracy and end_date_accuracy.
• Deprecate the start_date_accuracy and end_date_accuracy properties on the WorkZoneRoadEvent object; use the new is_start_date_verified and is_end_date_verified properties instead.
• Deprecate the event_status property on the WorkZoneRoadEvent object.
• Change the conformance of the road_names property on the FieldDeviceCoreDetails from "Required" to "Optional".
• Deprecate the traffic-signal value in the MarkedLocationType enumerated type; use the new TrafficSignal object instead.
• Deprecate the center-left-turn-lane value in the LaneType enumerated type; use the new two-way-center-turn-lane instead.
• Add a related_road_events property (and new supporting object RelatedRoadEvent and enumerated type RelatedRoadEventType) to the RoadEventCoreDetails to allow explicitly defining relationships/connections between road events; this replaces the Relationship object concept.
• Deprecate the relationship property on the RoadEventCoreDetails; use the new related_road_events property instead.

Cleanup

• Change the type of the average_speed_kph, volume_vph, and occupancy_percent properties on the TrafficSensor and TrafficSensorLaneData object from "Integer" to "Number"
• Change the allowed minimum value for average_speed_kph on TrafficSensorLaneData from 1 to 0.
• Add a feed_info property to the WorkZoneFeed object to replace the road_event_feed_info.
• Expand the description of the update_date property on the RoadEventCoreDetails and FieldDeviceCoreDetails to clarify what the value represents.
• Remove the RoadRestrictionFeed (it moved to usdot-jpo-ode/TDx).

WZDx Specification v4.0

WZDx version 4.0 implements clean up and small additions in functionality to the WZDx feed and adds definitions for two new feeds, the SwzDeviceFeed and RoadRestrictionFeed. Until version 4.0, the WZDx specification defined only one feed, the WZDxFeed.

Features

• Add the following values to the VehicleImpact enumerated type:
  • some-lanes-closed-merge-left
  • some-lanes-closed-merge-right
  • all-lanes-open-shift-left
  • all-lanes-open-shift-right
  • some-lanes-closed-split
  • flagging
  • temporary-traffic-signal
• Allow restrictions with a value and unit to be provided at the road event level; specifically:
  • Rename the LaneRestrictionUnit enumerated type to UnitOfMeasurement.
  • Rename the RoadRestriction enumerated type to RestrictionType.
  • Rename the LaneRestriction object to Restriction and remove the lane_restriction_ prefix from its properties.
  • Rename the Restriction object units property to unit.
• Add values parking and median to the LaneType enumerated type.
• Define a new data feed, the RoadRestrictionFeed and RestrictionRoadEvent to enable providing a feed of restrictions on roadways, such as bridge clearances.
• Define a new data feed, the SwzDeviceFeed, to enable equipment vendors and manufacturers to provide high-level information about deployed field devices in work zones. A SwzDeviceFeed contains a new feature type, the FieldDeviceFeature, which contains information about a specific type of field device. The following field devices are defined in WZDx v4.0:
  • ArrowBoard: An electronic, connected arrow board which can display an arrow pattern to direct traffic.
  • Camera: A camera device deployed in the field, capable of capturing still images.
  • DynamicMessageSign: An electronic traffic sign deployed on the roadway, used to provide information to travelers.
  • FlashingBeacon: A flashing beacon light of any form (e.g. trailer-mounted, vehicle), used to indicate something or capture driver attention.
  • HybridSign: A hybrid sign that contains static text (e.g. on an aluminum sign) along with a single electronic message display, used to provide information to travelers.
  • LocationMarker: Describes any GPS-enabled ITS device that is placed at a point on a roadway to dynamically know the location of something (often the beginning or end of a work zone).
  • TrafficSensor: A traffic sensor deployed on a roadway which captures traffic metrics (e.g. speed, volume, occupancy) over a collection interval.
• Rename the workers_present property on the WorkZoneRoadEvent object to worker_presence; change the type from "boolean" to a new WorkerPresence object which enables providing more nuanced information about worker presence in work zones.

Refactoring

• Separate the v3.1 RoadEvent object into RoadEventCoreDetails (details that are shared by all specific types of road events) and specific types of road events (WorkZoneRoadEvent, DetourRoadEvent, and RestrictionRoadEvent) which each contain the RoadEventCoreDetails via a core_details property; update the RoadEventFeature properties property to be one of the specific road events types.
• Move the location_method property from the FeedDataSource object to the WorkZoneRoadEvent object.
• Change the reduced_speed_limit property on the WorkZoneRoadEvent to reduced_speed_limit_kph; change its type from "integer" to "number" and clarify that the value should be in kilometers per hour.
• Deprecate the lane_number property on the Lane object.
• Deprecate the lrs_type and lrs_url properties on the FeedDataSource object.
• Remove the deprecated value alternating-one-way from the LaneStatus enumerated type.
• Remove the following deprecated properties from the road event (RoadEvent in previous versions; WorkZoneRoadEvent and RoadEventCoreDetails in 4.0):
  • road_event_id
  • road_number
  • road_name
  • total_num_lanes
• Remove the following deprecated values from the LaneType enumerated type:
  • left-lane
  • right-lane
  • middle-lane
  • center-lane
  • right-shoulder
  • left-shoulder
  • right-second-exit-ramp
  • left-second-exit-ramp
  • right-entrance-exit-ramp
  • left-entrance-exit-ramp
  • hov-lane
  • alternating-flow-lane
  • reversible-lane
  • right-entrance-lane
  • left-entrance-lane
  • left-entrance-ramp
  • right-merging-lane
  • left-merging-lane
  • right-second-entrance-ramp
  • left-second-entrance-ramp
• Require the road_names property on the RoadEventCoreDetails.
• Require the id property on the RoadEventFeature.
• Refine the LaneType enumerated type; specifically:
  • Rename lane to general.
  • Remove right-turning-lane and left-turning-lane.
  • Remove right-exit-lane and left-exit-lane.
  • Add exit-lane.
  • Remove right-exit-ramp and left-exit-ramp.
  • Add exit-ramp.
  • Remove right-entrance-ramp and left-exit-ramp.
  • Add entrance-ramp.
  • Add entrance-lane.
• Deprecate the location_verify_method property on the FeedDataSource.
• Update the SpatialVerification enumerated type value descriptions to clarify that verified work zone locations should use a GPS enabled device.

WZDx Specification v3.1

WZDx specification v3.1 released in April 2021. Following the major v3.0 release, the changes for the v3.1 release were developed with the goal enhancing and cleaning up the specification without making major changes or breaking backwards compatibility. Thus, in v3.1 many enumerated type values or object properties were deprecated rather than removed. Most if not all of these deprecated values will be removed in the next major release.

Features

• Add local-access-only restriction
• Add license property to the RoadEventFeedInfo object

Refactoring

• Refactor LaneType enumerated type to deprecate values that can be determined from other properties of the Lane object, such as order, status, and lane_restrictions
• Add value alternating-flow to LaneStatus enumerated type and deprecate alternating-one-way
• Add road_names property to the RoadEvent object and deprecate road_name and road_number
• Deprecate the total_num_lanes property on the RoadEvent object as the RoadEvent's lanes array can be used to determine the number of lanes

Fixes

• Add optional bbox property to allow providing a GeoJSON Bounding Box for the WZDxFeed and RoadEventFeature objects
• Add an id property to the RoadEventFeature object for providing the a road event's identifier to better follow GeoJSON ID recommendations

WZDx Specification v3.0

WZDx specification v3.0 released on 9/18/2020. This version sees the following changes, as well as consistency/cleanup of all the markdown files in the repository:

Features

• Restrict version format to major.minor and enforce via v3.0 JSON schema
• Add order property to lane entity to indicate a lane's position in sequence on the roadway
• Remove lane_edge_reference and standardize on counting lanes from the left side of the roadway
• Add event_type property to the road event entity and new Event Type Enumerated Type with the values work-zone and detour, to support adding detour information (and more in the future)
• Add relationship entity (one per road event entity) to enable describing relationships (hierarchical and sequential) between road events and other non-WZDx entities (such as a work zone phase or project)
• Add road_event_data_source entity to allow specifying multiple data sources within a single feed
• Streamline metadata (previously given in an external file, by URL) and add relevant fields to the road_event_feed_info and road_event_data_source entities

Fixes

• Require restriction_type if providing a lane-level restriction
• Change Spatial Verification Enumerated Type and Time Verification Enumerated Type values to be all lowercase
• Remove all plural or nonsensical lane types from the Lane Type Enumerated Type and clarify that each WZDx lane should represent a single lane on the roadway

WZDx Specification v2.0

WZDx specification v2.0 released on 1/14/2020. This version adopted a relational data model approach to eliminate nested tables and make the specification more scalable. The specification requires feeds to be published in GeoJSON format to facilitate data consumption and use. New simplified road closure impact reporting to indicate whether a road is partially closed, fully closed, or fully open has been added to the specification. The specification captures work type as well as lane-level restrictions (when available) to specify work zone impacts for each lane of a roadway.

WZDx Specification v1.1

WZDx specification v1.1 released on 9/15/2018. This version served as a first step in providing a standard work zone data activity framework. This version of the specification focused on “common core” data concepts which are defined as data elements needed for most work zone data use cases. The specification included data elements that data producers were already producing as well as those that may not currently be produced.