package transit_realtime

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An alert, indicating some sort of incident in the public transit network.

Used in: FeedEntity

• repeated TimeRange active_period = 1

  Time when the alert should be shown to the user. If missing, the alert will be shown as long as it appears in the feed. If multiple ranges are given, the alert will be shown during all of them.

• repeated EntitySelector informed_entity = 5

  Entities whose users we should notify of this alert.

• optional Alert.Cause cause = 6

• optional Alert.Effect effect = 7

• optional TranslatedString url = 8

  The URL which provides additional information about the alert.

• optional TranslatedString header_text = 10

  Alert header. Contains a short summary of the alert text as plain-text.

• optional TranslatedString description_text = 11

  Full description for the alert as plain-text. The information in the description should add to the information of the header.

Cause of this alert.

Used in: Alert

• UNKNOWN_CAUSE = 1

• OTHER_CAUSE = 2

  Not machine-representable.

• TECHNICAL_PROBLEM = 3

• STRIKE = 4

  Public transit agency employees stopped working.

• DEMONSTRATION = 5

  People are blocking the streets.

• ACCIDENT = 6

• HOLIDAY = 7

• WEATHER = 8

• MAINTENANCE = 9

• CONSTRUCTION = 10

• POLICE_ACTIVITY = 11

• MEDICAL_EMERGENCY = 12

What is the effect of this problem on the affected entity.

Used in: Alert

• NO_SERVICE = 1

• REDUCED_SERVICE = 2

• SIGNIFICANT_DELAYS = 3

  We don't care about INsignificant delays: they are hard to detect, have little impact on the user, and would clutter the results as they are too frequent.

• DETOUR = 4

• ADDITIONAL_SERVICE = 5

• MODIFIED_SERVICE = 6

• OTHER_EFFECT = 7

• UNKNOWN_EFFECT = 8

• STOP_MOVED = 9

A selector for an entity in a GTFS feed.

Used in: Alert

• optional string agency_id = 1

  The values of the fields should correspond to the appropriate fields in the GTFS feed. At least one specifier must be given. If several are given, then the matching has to apply to all the given specifiers.

• optional string route_id = 2

• optional int32 route_type = 3

  corresponds to route_type in GTFS.

• optional TripDescriptor trip = 4

• optional string stop_id = 5

A definition (or update) of an entity in the transit feed.

Used in: FeedMessage

• required string id = 1

  The ids are used only to provide incrementality support. The id should be unique within a FeedMessage. Consequent FeedMessages may contain FeedEntities with the same id. In case of a DIFFERENTIAL update the new FeedEntity with some id will replace the old FeedEntity with the same id (or delete it - see is_deleted below). The actual GTFS entities (e.g. stations, routes, trips) referenced by the feed must be specified by explicit selectors (see EntitySelector below for more info).

• optional bool is_deleted = 2

  Whether this entity is to be deleted. Relevant only for incremental fetches.

• optional TripUpdate trip_update = 3

  Data about the entity itself. Exactly one of the following fields must be present (unless the entity is being deleted).

• optional VehiclePosition vehicle = 4

• optional Alert alert = 5

Metadata about a feed, included in feed messages.

Used in: FeedMessage

• required string gtfs_realtime_version = 1

  Version of the feed specification. The current version is 2.0.

• optional FeedHeader.Incrementality incrementality = 2

• optional uint64 timestamp = 3

  This timestamp identifies the moment when the content of this feed has been created (in server time). In POSIX time (i.e., number of seconds since January 1st 1970 00:00:00 UTC).

Determines whether the current fetch is incremental. Currently, DIFFERENTIAL mode is unsupported and behavior is unspecified for feeds that use this mode. There are discussions on the GTFS Realtime mailing list around fully specifying the behavior of DIFFERENTIAL mode and the documentation will be updated when those discussions are finalized.

Used in: FeedHeader

• FULL_DATASET = 0

• DIFFERENTIAL = 1

The contents of a feed message. A feed is a continuous stream of feed messages. Each message in the stream is obtained as a response to an appropriate HTTP GET request. A realtime feed is always defined with relation to an existing GTFS feed. All the entity ids are resolved with respect to the GTFS feed. Note that "required" and "optional" as stated in this file refer to Protocol Buffer cardinality, not semantic cardinality. See reference.md at https://github.com/google/transit/tree/master/gtfs-realtime for field semantic cardinality.

• required FeedHeader header = 1

  Metadata about this feed and feed message.

• repeated FeedEntity entity = 2

  Contents of the feed.

A position.

Used in: VehiclePosition

• required float latitude = 1

  Degrees North, in the WGS-84 coordinate system.

• required float longitude = 2

  Degrees East, in the WGS-84 coordinate system.

• optional float bearing = 3

  Bearing, in degrees, clockwise from North, i.e., 0 is North and 90 is East. This can be the compass bearing, or the direction towards the next stop or intermediate location. This should not be direction deduced from the sequence of previous positions, which can be computed from previous data.

• optional double odometer = 4

  Odometer value, in meters.

• optional float speed = 5

  Momentary speed measured by the vehicle, in meters per second.

A time interval. The interval is considered active at time 't' if 't' is greater than or equal to the start time and less than the end time.

Used in: Alert

• optional uint64 start = 1

  Start time, in POSIX time (i.e., number of seconds since January 1st 1970 00:00:00 UTC). If missing, the interval starts at minus infinity.

• optional uint64 end = 2

  End time, in POSIX time (i.e., number of seconds since January 1st 1970 00:00:00 UTC). If missing, the interval ends at plus infinity.

An internationalized message containing per-language versions of a snippet of text or a URL. One of the strings from a message will be picked up. The resolution proceeds as follows: 1. If the UI language matches the language code of a translation, the first matching translation is picked. 2. If a default UI language (e.g., English) matches the language code of a translation, the first matching translation is picked. 3. If some translation has an unspecified language code, that translation is picked.

Used in: Alert

• repeated TranslatedString.Translation translation = 1

  At least one translation must be provided.

Used in: TranslatedString

• required string text = 1

  A UTF-8 string containing the message.

• optional string language = 2

  BCP-47 language code. Can be omitted if the language is unknown or if no i18n is done at all for the feed. At most one translation is allowed to have an unspecified language tag.

A descriptor that identifies an instance of a GTFS trip, or all instances of a trip along a route. - To specify a single trip instance, the trip_id (and if necessary, start_time) is set. If route_id is also set, then it should be same as one that the given trip corresponds to. - To specify all the trips along a given route, only the route_id should be set. Note that if the trip_id is not known, then stop sequence ids in TripUpdate are not sufficient, and stop_ids must be provided as well. In addition, absolute arrival/departure times must be provided.

Used in: EntitySelector, TripUpdate, VehiclePosition

• optional string trip_id = 1

  The trip_id from the GTFS feed that this selector refers to. For non frequency-based trips, this field is enough to uniquely identify the trip. For frequency-based trip, start_time and start_date might also be necessary.

• optional string route_id = 5

  The route_id from the GTFS that this selector refers to.

• optional uint32 direction_id = 6

  The direction_id from the GTFS feed trips.txt file, indicating the direction of travel for trips this selector refers to. This field is still experimental, and subject to change. It may be formally adopted in the future.

• optional string start_time = 2

  The initially scheduled start time of this trip instance. When the trip_id corresponds to a non-frequency-based trip, this field should either be omitted or be equal to the value in the GTFS feed. When the trip_id correponds to a frequency-based trip, the start_time must be specified for trip updates and vehicle positions. If the trip corresponds to exact_times=1 GTFS record, then start_time must be some multiple (including zero) of headway_secs later than frequencies.txt start_time for the corresponding time period. If the trip corresponds to exact_times=0, then its start_time may be arbitrary, and is initially expected to be the first departure of the trip. Once established, the start_time of this frequency-based trip should be considered immutable, even if the first departure time changes -- that time change may instead be reflected in a StopTimeUpdate. Format and semantics of the field is same as that of GTFS/frequencies.txt/start_time, e.g., 11:15:35 or 25:15:35.

• optional string start_date = 3

  The scheduled start date of this trip instance. Must be provided to disambiguate trips that are so late as to collide with a scheduled trip on a next day. For example, for a train that departs 8:00 and 20:00 every day, and is 12 hours late, there would be two distinct trips on the same time. This field can be provided but is not mandatory for schedules in which such collisions are impossible - for example, a service running on hourly schedule where a vehicle that is one hour late is not considered to be related to schedule anymore. In YYYYMMDD format.

• optional TripDescriptor.ScheduleRelationship schedule_relationship = 4

The relation between this trip and the static schedule. If a trip is done in accordance with temporary schedule, not reflected in GTFS, then it shouldn't be marked as SCHEDULED, but likely as ADDED.

Used in: TripDescriptor

• SCHEDULED = 0

  Trip that is running in accordance with its GTFS schedule, or is close enough to the scheduled trip to be associated with it.

• ADDED = 1

  An extra trip that was added in addition to a running schedule, for example, to replace a broken vehicle or to respond to sudden passenger load.

• UNSCHEDULED = 2

  A trip that is running with no schedule associated to it, for example, if there is no schedule at all.

• CANCELED = 3

  A trip that existed in the schedule but was removed.

Realtime update of the progress of a vehicle along a trip. Depending on the value of ScheduleRelationship, a TripUpdate can specify: - A trip that proceeds along the schedule. - A trip that proceeds along a route but has no fixed schedule. - A trip that have been added or removed with regard to schedule. The updates can be for future, predicted arrival/departure events, or for past events that already occurred. Normally, updates should get more precise and more certain (see uncertainty below) as the events gets closer to current time. Even if that is not possible, the information for past events should be precise and certain. In particular, if an update points to time in the past but its update's uncertainty is not 0, the client should conclude that the update is a (wrong) prediction and that the trip has not completed yet. Note that the update can describe a trip that is already completed. To this end, it is enough to provide an update for the last stop of the trip. If the time of that is in the past, the client will conclude from that that the whole trip is in the past (it is possible, although inconsequential, to also provide updates for preceding stops). This option is most relevant for a trip that has completed ahead of schedule, but according to the schedule, the trip is still proceeding at the current time. Removing the updates for this trip could make the client assume that the trip is still proceeding. Note that the feed provider is allowed, but not required, to purge past updates - this is one case where this would be practically useful.

Used in: FeedEntity

• required TripDescriptor trip = 1

  The Trip that this message applies to. There can be at most one TripUpdate entity for each actual trip instance. If there is none, that means there is no prediction information available. It does *not* mean that the trip is progressing according to schedule.

• optional VehicleDescriptor vehicle = 3

  Additional information on the vehicle that is serving this trip.

• repeated TripUpdate.StopTimeUpdate stop_time_update = 2

  Updates to StopTimes for the trip (both future, i.e., predictions, and in some cases, past ones, i.e., those that already happened). The updates must be sorted by stop_sequence, and apply for all the following stops of the trip up to the next specified one. Example 1: For a trip with 20 stops, a StopTimeUpdate with arrival delay and departure delay of 0 for stop_sequence of the current stop means that the trip is exactly on time. Example 2: For the same trip instance, 3 StopTimeUpdates are provided: - delay of 5 min for stop_sequence 3 - delay of 1 min for stop_sequence 8 - delay of unspecified duration for stop_sequence 10 This will be interpreted as: - stop_sequences 3,4,5,6,7 have delay of 5 min. - stop_sequences 8,9 have delay of 1 min. - stop_sequences 10,... have unknown delay.

• optional uint64 timestamp = 4

  Moment at which the vehicle's real-time progress was measured. In POSIX time (i.e., the number of seconds since January 1st 1970 00:00:00 UTC).

• optional int32 delay = 5

  The current schedule deviation for the trip. Delay should only be specified when the prediction is given relative to some existing schedule in GTFS. Delay (in seconds) can be positive (meaning that the vehicle is late) or negative (meaning that the vehicle is ahead of schedule). Delay of 0 means that the vehicle is exactly on time. Delay information in StopTimeUpdates take precedent of trip-level delay information, such that trip-level delay is only propagated until the next stop along the trip with a StopTimeUpdate delay value specified. Feed providers are strongly encouraged to provide a TripUpdate.timestamp value indicating when the delay value was last updated, in order to evaluate the freshness of the data. NOTE: This field is still experimental, and subject to change. It may be formally adopted in the future.

Timing information for a single predicted event (either arrival or departure). Timing consists of delay and/or estimated time, and uncertainty. - delay should be used when the prediction is given relative to some existing schedule in GTFS. - time should be given whether there is a predicted schedule or not. If both time and delay are specified, time will take precedence (although normally, time, if given for a scheduled trip, should be equal to scheduled time in GTFS + delay). Uncertainty applies equally to both time and delay. The uncertainty roughly specifies the expected error in true delay (but note, we don't yet define its precise statistical meaning). It's possible for the uncertainty to be 0, for example for trains that are driven under computer timing control.

Used in: StopTimeUpdate

• optional int32 delay = 1

  Delay (in seconds) can be positive (meaning that the vehicle is late) or negative (meaning that the vehicle is ahead of schedule). Delay of 0 means that the vehicle is exactly on time.

• optional int64 time = 2

  Event as absolute time. In Unix time (i.e., number of seconds since January 1st 1970 00:00:00 UTC).

• optional int32 uncertainty = 3

  If uncertainty is omitted, it is interpreted as unknown. If the prediction is unknown or too uncertain, the delay (or time) field should be empty. In such case, the uncertainty field is ignored. To specify a completely certain prediction, set its uncertainty to 0.

Realtime update for arrival and/or departure events for a given stop on a trip. Updates can be supplied for both past and future events. The producer is allowed, although not required, to drop past events.

The update is linked to a specific stop either through stop_sequence or stop_id, so one of the fields below must necessarily be set. See the documentation in TripDescriptor for more information.

Used in: TripUpdate

• optional uint32 stop_sequence = 1

  Must be the same as in stop_times.txt in the corresponding GTFS feed.

• optional string stop_id = 4

  Must be the same as in stops.txt in the corresponding GTFS feed.

• optional StopTimeEvent arrival = 2

• optional StopTimeEvent departure = 3

• optional StopTimeUpdate.ScheduleRelationship schedule_relationship = 5

The relation between this StopTime and the static schedule.

Used in: StopTimeUpdate

• SCHEDULED = 0

  The vehicle is proceeding in accordance with its static schedule of stops, although not necessarily according to the times of the schedule. At least one of arrival and departure must be provided. If the schedule for this stop contains both arrival and departure times then so must this update.

• SKIPPED = 1

  The stop is skipped, i.e., the vehicle will not stop at this stop. Arrival and departure are optional.

• NO_DATA = 2

  No data is given for this stop. The main intention for this value is to give the predictions only for part of a trip, i.e., if the last update for a trip has a NO_DATA specifier, then StopTimes for the rest of the stops in the trip are considered to be unspecified as well. Neither arrival nor departure should be supplied.

Identification information for the vehicle performing the trip.

Used in: TripUpdate, VehiclePosition

• optional string id = 1

  Internal system identification of the vehicle. Should be unique per vehicle, and can be used for tracking the vehicle as it proceeds through the system.

• optional string label = 2

  User visible label, i.e., something that must be shown to the passenger to help identify the correct vehicle.

• optional string license_plate = 3

  The license plate of the vehicle.

Realtime positioning information for a given vehicle.

Used in: FeedEntity

• optional TripDescriptor trip = 1

  The Trip that this vehicle is serving. Can be empty or partial if the vehicle can not be identified with a given trip instance.

• optional VehicleDescriptor vehicle = 8

  Additional information on the vehicle that is serving this trip.

• optional Position position = 2

  Current position of this vehicle.

• optional uint32 current_stop_sequence = 3

  The stop sequence index of the current stop. The meaning of current_stop_sequence (i.e., the stop that it refers to) is determined by current_status. If current_status is missing IN_TRANSIT_TO is assumed.

• optional string stop_id = 7

  Identifies the current stop. The value must be the same as in stops.txt in the corresponding GTFS feed.

• optional VehiclePosition.VehicleStopStatus current_status = 4

  The exact status of the vehicle with respect to the current stop. Ignored if current_stop_sequence is missing.

• optional uint64 timestamp = 5

  Moment at which the vehicle's position was measured. In POSIX time (i.e., number of seconds since January 1st 1970 00:00:00 UTC).

• optional VehiclePosition.CongestionLevel congestion_level = 6

• optional VehiclePosition.OccupancyStatus occupancy_status = 9

Congestion level that is affecting this vehicle.

Used in: VehiclePosition

• UNKNOWN_CONGESTION_LEVEL = 0

• RUNNING_SMOOTHLY = 1

• STOP_AND_GO = 2

• CONGESTION = 3

• SEVERE_CONGESTION = 4

  People leaving their cars.

The degree of passenger occupancy of the vehicle. This field is still experimental, and subject to change. It may be formally adopted in the future.

Used in: VehiclePosition

• EMPTY = 0

  The vehicle is considered empty by most measures, and has few or no passengers onboard, but is still accepting passengers.

• MANY_SEATS_AVAILABLE = 1

  The vehicle has a relatively large percentage of seats available. What percentage of free seats out of the total seats available is to be considered large enough to fall into this category is determined at the discretion of the producer.

• FEW_SEATS_AVAILABLE = 2

  The vehicle has a relatively small percentage of seats available. What percentage of free seats out of the total seats available is to be considered small enough to fall into this category is determined at the discretion of the feed producer.

• STANDING_ROOM_ONLY = 3

  The vehicle can currently accommodate only standing passengers.

• CRUSHED_STANDING_ROOM_ONLY = 4

  The vehicle can currently accommodate only standing passengers and has limited space for them.

• FULL = 5

  The vehicle is considered full by most measures, but may still be allowing passengers to board.

• NOT_ACCEPTING_PASSENGERS = 6

  The vehicle is not accepting additional passengers.

Used in: VehiclePosition

• INCOMING_AT = 0

  The vehicle is just about to arrive at the stop (on a stop display, the vehicle symbol typically flashes).

• STOPPED_AT = 1

  The vehicle is standing at the stop.

• IN_TRANSIT_TO = 2

  The vehicle has departed and is in transit to the next stop.