GTFS Realtime Protobuf¶
Download the gtfs-realtime.proto file and use it to compile your GTFS-realtime feed. The contents of the file are shown inline below. For more information about using protobufs, see the Protocol Buffers Developer Guide.
// Copyright 2015 The GTFS Specifications Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Protocol definition file for GTFS Realtime.
//
// GTFS Realtime lets transit agencies provide consumers with realtime
// information about disruptions to their service (stations closed, lines not
// operating, important delays etc), location of their vehicles and expected
// arrival times.
//
// This protocol is published at:
// https://github.com/google/transit/tree/master/gtfs-realtime
syntax = "proto2";
option java_package = "com.google.transit.realtime";
package transit_realtime;
// 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.
message FeedMessage {
// Metadata about this feed and feed message.
required FeedHeader header = 1;
// Contents of the feed.
repeated FeedEntity entity = 2;
// The extensions namespace allows 3rd-party developers to extend the
// GTFS Realtime specification in order to add and evaluate new features and
// modifications to the spec.
extensions 1000 to 1999;
// The following extension IDs are reserved for private use by any organization.
extensions 9000 to 9999;
}
// Metadata about a feed, included in feed messages.
message FeedHeader {
// Version of the feed specification.
// The current version is 2.0. Valid versions are "2.0", "1.0".
required string gtfs_realtime_version = 1;
// 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.
enum Incrementality {
FULL_DATASET = 0;
DIFFERENTIAL = 1;
}
optional Incrementality incrementality = 2 [default = FULL_DATASET];
// 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).
optional uint64 timestamp = 3;
// The extensions namespace allows 3rd-party developers to extend the
// GTFS Realtime specification in order to add and evaluate new features and
// modifications to the spec.
extensions 1000 to 1999;
// The following extension IDs are reserved for private use by any organization.
extensions 9000 to 9999;
}
// A definition (or update) of an entity in the transit feed.
message FeedEntity {
// 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).
required string id = 1;
// Whether this entity is to be deleted. Relevant only for incremental
// fetches.
optional bool is_deleted = 2 [default = false];
// Data about the entity itself. Exactly one of the following fields must be
// present (unless the entity is being deleted).
optional TripUpdate trip_update = 3;
optional VehiclePosition vehicle = 4;
optional Alert alert = 5;
// NOTE: This field is still experimental, and subject to change. It may be formally adopted in the future.
optional Shape shape = 6;
optional Stop stop = 7;
optional TripModifications trip_modifications = 8;
// The extensions namespace allows 3rd-party developers to extend the
// GTFS Realtime Specification in order to add and evaluate new features and
// modifications to the spec.
extensions 1000 to 1999;
// The following extension IDs are reserved for private use by any organization.
extensions 9000 to 9999;
}
//
// Entities used in the feed.
//
// 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.
message TripUpdate {
// 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.
required TripDescriptor trip = 1;
// Additional information on the vehicle that is serving this trip.
optional VehicleDescriptor vehicle = 3;
// 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.
message StopTimeEvent {
// 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 int32 delay = 1;
// Event as absolute time.
// In Unix time (i.e., number of seconds since January 1st 1970 00:00:00
// UTC).
optional int64 time = 2;
// 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.
optional int32 uncertainty = 3;
// The extensions namespace allows 3rd-party developers to extend the
// GTFS Realtime Specification in order to add and evaluate new features
// and modifications to the spec.
extensions 1000 to 1999;
// The following extension IDs are reserved for private use by any organization.
extensions 9000 to 9999;
}
// 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.
message StopTimeUpdate {
// 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.
// Must be the same as in stop_times.txt in the corresponding GTFS feed.
optional uint32 stop_sequence = 1;
// Must be the same as in stops.txt in the corresponding GTFS feed.
optional string stop_id = 4;
optional StopTimeEvent arrival = 2;
optional StopTimeEvent departure = 3;
// Expected occupancy after departure from the given stop.
// Should be provided only for future stops.
// In order to provide departure_occupancy_status without either arrival or
// departure StopTimeEvents, ScheduleRelationship should be set to NO_DATA.
optional VehiclePosition.OccupancyStatus departure_occupancy_status = 7;
// The relation between the StopTimeEvents and the static schedule.
enum ScheduleRelationship {
// 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. Frequency-based trips (GTFS frequencies.txt with exact_times = 0)
// should not have a SCHEDULED value and should use UNSCHEDULED instead.
SCHEDULED = 0;
// The stop is skipped, i.e., the vehicle will not stop at this stop.
// Arrival and departure are optional.
SKIPPED = 1;
// No StopTimeEvents are given for this stop.
// The main intention for this value is to give time predictions only for
// part of a trip, i.e., if the last update for a trip has a NO_DATA
// specifier, then StopTimeEvents for the rest of the stops in the trip
// are considered to be unspecified as well.
// Neither arrival nor departure should be supplied.
NO_DATA = 2;
// The vehicle is operating a trip defined in GTFS frequencies.txt with exact_times = 0.
// This value should not be used for trips that are not defined in GTFS frequencies.txt,
// or trips in GTFS frequencies.txt with exact_times = 1. Trips containing StopTimeUpdates
// with ScheduleRelationship=UNSCHEDULED must also set TripDescriptor.ScheduleRelationship=UNSCHEDULED.
// NOTE: This field is still experimental, and subject to change. It may be
// formally adopted in the future.
UNSCHEDULED = 3;
}
optional ScheduleRelationship schedule_relationship = 5
[default = SCHEDULED];
// Provides the updated values for the stop time.
// NOTE: This message is still experimental, and subject to change. It may be formally adopted in the future.
message StopTimeProperties {
// Supports real-time stop assignments. Refers to a stop_id defined in the GTFS stops.txt.
// The new assigned_stop_id should not result in a significantly different trip experience for the end user than
// the stop_id defined in GTFS stop_times.txt. In other words, the end user should not view this new stop_id as an
// "unusual change" if the new stop was presented within an app without any additional context.
// For example, this field is intended to be used for platform assignments by using a stop_id that belongs to the
// same station as the stop originally defined in GTFS stop_times.txt.
// To assign a stop without providing any real-time arrival or departure predictions, populate this field and set
// StopTimeUpdate.schedule_relationship = NO_DATA.
// If this field is populated, it is preferred to omit `StopTimeUpdate.stop_id` and use only `StopTimeUpdate.stop_sequence`. If
// `StopTimeProperties.assigned_stop_id` and `StopTimeUpdate.stop_id` are populated, `StopTimeUpdate.stop_id` must match `assigned_stop_id`.
// Platform assignments should be reflected in other GTFS-realtime fields as well
// (e.g., `VehiclePosition.stop_id`).
// NOTE: This field is still experimental, and subject to change. It may be formally adopted in the future.
optional string assigned_stop_id = 1;
// The extensions namespace allows 3rd-party developers to extend the
// GTFS Realtime Specification in order to add and evaluate new features
// and modifications to the spec.
extensions 1000 to 1999;
// The following extension IDs are reserved for private use by any organization.
extensions 9000 to 9999;
}
// Realtime updates for certain properties defined within GTFS stop_times.txt
// NOTE: This field is still experimental, and subject to change. It may be formally adopted in the future.
optional StopTimeProperties stop_time_properties = 6;
// The extensions namespace allows 3rd-party developers to extend the
// GTFS Realtime Specification in order to add and evaluate new features
// and modifications to the spec.
extensions 1000 to 1999;
// The following extension IDs are reserved for private use by any organization.
extensions 9000 to 9999;
}
// 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.
repeated StopTimeUpdate stop_time_update = 2;
// The most recent moment at which the vehicle's real-time progress was measured
// to estimate StopTimes in the future. When StopTimes in the past are provided,
// arrival/departure times may be earlier than this value. In POSIX
// time (i.e., the number of seconds since January 1st 1970 00:00:00 UTC).
optional uint64 timestamp = 4;
// 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.
optional int32 delay = 5;
// Defines updated properties of the trip, such as a new shape_id when there is a detour. Or defines the
// trip_id, start_date, and start_time of a DUPLICATED trip.
// NOTE: This message is still experimental, and subject to change. It may be formally adopted in the future.
message TripProperties {
// Defines the identifier of a new trip that is a duplicate of an existing trip defined in (CSV) GTFS trips.txt
// but will start at a different service date and/or time (defined using the TripProperties.start_date and
// TripProperties.start_time fields). See definition of trips.trip_id in (CSV) GTFS. Its value must be different
// than the ones used in the (CSV) GTFS. Required if schedule_relationship=DUPLICATED, otherwise this field must not
// be populated and will be ignored by consumers.
// NOTE: This field is still experimental, and subject to change. It may be formally adopted in the future.
optional string trip_id = 1;
// Service date on which the DUPLICATED trip will be run, in YYYYMMDD format. Required if
// schedule_relationship=DUPLICATED, otherwise this field must not be populated and will be ignored by consumers.
// NOTE: This field is still experimental, and subject to change. It may be formally adopted in the future.
optional string start_date = 2;
// Defines the departure start time of the trip when it’s duplicated. See definition of stop_times.departure_time
// in (CSV) GTFS. Scheduled arrival and departure times for the duplicated trip are calculated based on the offset
// between the original trip departure_time and this field. For example, if a GTFS trip has stop A with a
// departure_time of 10:00:00 and stop B with departure_time of 10:01:00, and this field is populated with the value
// of 10:30:00, stop B on the duplicated trip will have a scheduled departure_time of 10:31:00. Real-time prediction
// delay values are applied to this calculated schedule time to determine the predicted time. For example, if a
// departure delay of 30 is provided for stop B, then the predicted departure time is 10:31:30. Real-time
// prediction time values do not have any offset applied to them and indicate the predicted time as provided.
// For example, if a departure time representing 10:31:30 is provided for stop B, then the predicted departure time
// is 10:31:30. This field is required if schedule_relationship is DUPLICATED, otherwise this field must not be
// populated and will be ignored by consumers.
// NOTE: This field is still experimental, and subject to change. It may be formally adopted in the future.
optional string start_time = 3;
// Specifies the shape of the vehicle travel path when the trip shape differs from the shape specified in
// (CSV) GTFS or to specify it in real-time when it's not provided by (CSV) GTFS, such as a vehicle that takes differing
// paths based on rider demand. See definition of trips.shape_id in (CSV) GTFS. If a shape is neither defined in (CSV) GTFS
// nor in real-time, the shape is considered unknown. This field can refer to a shape defined in the (CSV) GTFS in shapes.txt
// or a Shape in the (protobuf) real-time feed. The order of stops (stop sequences) for this trip must remain the same as
// (CSV) GTFS. Stops that are a part of the original trip but will no longer be made, such as when a detour occurs, should
// be marked as schedule_relationship=SKIPPED.
// NOTE: This field is still experimental, and subject to change. It may be formally adopted in the future.
optional string shape_id = 4;
// The extensions namespace allows 3rd-party developers to extend the
// GTFS Realtime Specification in order to add and evaluate new features
// and modifications to the spec.
extensions 1000 to 1999;
// The following extension IDs are reserved for private use by any organization.
extensions 9000 to 9999;
}
optional TripProperties trip_properties = 6;
// The extensions namespace allows 3rd-party developers to extend the
// GTFS Realtime Specification in order to add and evaluate new features and
// modifications to the spec.
extensions 1000 to 1999;
// The following extension IDs are reserved for private use by any organization.
extensions 9000 to 9999;
}
// Realtime positioning information for a given vehicle.
message VehiclePosition {
// 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 TripDescriptor trip = 1;
// Additional information on the vehicle that is serving this trip.
optional VehicleDescriptor vehicle = 8;
// Current position of this vehicle.
optional Position position = 2;
// 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 uint32 current_stop_sequence = 3;
// Identifies the current stop. The value must be the same as in stops.txt in
// the corresponding GTFS feed.
optional string stop_id = 7;
enum VehicleStopStatus {
// The vehicle is just about to arrive at the stop (on a stop
// display, the vehicle symbol typically flashes).
INCOMING_AT = 0;
// The vehicle is standing at the stop.
STOPPED_AT = 1;
// The vehicle has departed and is in transit to the next stop.
IN_TRANSIT_TO = 2;
}
// The exact status of the vehicle with respect to the current stop.
// Ignored if current_stop_sequence is missing.
optional VehicleStopStatus current_status = 4 [default = IN_TRANSIT_TO];
// 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 uint64 timestamp = 5;
// Congestion level that is affecting this vehicle.
enum CongestionLevel {
UNKNOWN_CONGESTION_LEVEL = 0;
RUNNING_SMOOTHLY = 1;
STOP_AND_GO = 2;
CONGESTION = 3;
SEVERE_CONGESTION = 4; // People leaving their cars.
}
optional CongestionLevel congestion_level = 6;
// The state of passenger occupancy for the vehicle or carriage.
// Individual producers may not publish all OccupancyStatus values. Therefore, consumers
// must not assume that the OccupancyStatus values follow a linear scale.
// Consumers should represent OccupancyStatus values as the state indicated
// and intended by the producer. Likewise, producers must use OccupancyStatus values that
// correspond to actual vehicle occupancy states.
// For describing passenger occupancy levels on a linear scale, see `occupancy_percentage`.
// This field is still experimental, and subject to change. It may be formally adopted in the future.
enum OccupancyStatus {
// The vehicle or carriage is considered empty by most measures, and has few or no
// passengers onboard, but is still accepting passengers.
EMPTY = 0;
// The vehicle or carriage has a large number of seats available.
// The amount of free seats out of the total seats available to be
// considered large enough to fall into this category is determined at the
// discretion of the producer.
MANY_SEATS_AVAILABLE = 1;
// The vehicle or carriage has a relatively small number of seats available.
// The amount of free seats out of the total seats available to be
// considered small enough to fall into this category is determined at the
// discretion of the feed producer.
FEW_SEATS_AVAILABLE = 2;
// The vehicle or carriage can currently accommodate only standing passengers.
STANDING_ROOM_ONLY = 3;
// The vehicle or carriage can currently accommodate only standing passengers
// and has limited space for them.
CRUSHED_STANDING_ROOM_ONLY = 4;
// The vehicle or carriage is considered full by most measures, but may still be
// allowing passengers to board.
FULL = 5;
// The vehicle or carriage is not accepting passengers, but usually accepts passengers for boarding.
NOT_ACCEPTING_PASSENGERS = 6;
// The vehicle or carriage doesn't have any occupancy data available at that time.
NO_DATA_AVAILABLE = 7;
// The vehicle or carriage is not boardable and never accepts passengers.
// Useful for special vehicles or carriages (engine, maintenance carriage, etc…).
NOT_BOARDABLE = 8;
}
// If multi_carriage_status is populated with per-carriage OccupancyStatus,
// then this field should describe the entire vehicle with all carriages accepting passengers considered.
optional OccupancyStatus occupancy_status = 9;
// A percentage value indicating the degree of passenger occupancy in the vehicle.
// The values are represented as an integer without decimals. 0 means 0% and 100 means 100%.
// The value 100 should represent the total maximum occupancy the vehicle was designed for,
// including both seated and standing capacity, and current operating regulations allow.
// The value may exceed 100 if there are more passengers than the maximum designed capacity.
// The precision of occupancy_percentage should be low enough that individual passengers cannot be tracked boarding or alighting the vehicle.
// If multi_carriage_status is populated with per-carriage occupancy_percentage,
// then this field should describe the entire vehicle with all carriages accepting passengers considered.
// This field is still experimental, and subject to change. It may be formally adopted in the future.
optional uint32 occupancy_percentage = 10;
// Carriage specific details, used for vehicles composed of several carriages
// This message/field is still experimental, and subject to change. It may be formally adopted in the future.
message CarriageDetails {
// Identification of the carriage. Should be unique per vehicle.
optional string id = 1;
// User visible label that may be shown to the passenger to help identify
// the carriage. Example: "7712", "Car ABC-32", etc...
// This message/field is still experimental, and subject to change. It may be formally adopted in the future.
optional string label = 2;
// Occupancy status for this given carriage, in this vehicle
// This message/field is still experimental, and subject to change. It may be formally adopted in the future.
optional OccupancyStatus occupancy_status = 3 [default = NO_DATA_AVAILABLE];
// Occupancy percentage for this given carriage, in this vehicle.
// Follows the same rules as "VehiclePosition.occupancy_percentage"
// -1 in case data is not available for this given carriage (as protobuf defaults to 0 otherwise)
// This message/field is still experimental, and subject to change. It may be formally adopted in the future.
optional int32 occupancy_percentage = 4 [default = -1];
// Identifies the order of this carriage with respect to the other
// carriages in the vehicle's list of CarriageDetails.
// The first carriage in the direction of travel must have a value of 1.
// The second value corresponds to the second carriage in the direction
// of travel and must have a value of 2, and so forth.
// For example, the first carriage in the direction of travel has a value of 1.
// If the second carriage in the direction of travel has a value of 3,
// consumers will discard data for all carriages (i.e., the multi_carriage_details field).
// Carriages without data must be represented with a valid carriage_sequence number and the fields
// without data should be omitted (alternately, those fields could also be included and set to the "no data" values).
// This message/field is still experimental, and subject to change. It may be formally adopted in the future.
optional uint32 carriage_sequence = 5;
// The extensions namespace allows 3rd-party developers to extend the
// GTFS Realtime Specification in order to add and evaluate new features and
// modifications to the spec.
extensions 1000 to 1999;
// The following extension IDs are reserved for private use by any organization.
extensions 9000 to 9999;
}
// Details of the multiple carriages of this given vehicle.
// The first occurrence represents the first carriage of the vehicle,
// given the current direction of travel.
// The number of occurrences of the multi_carriage_details
// field represents the number of carriages of the vehicle.
// It also includes non boardable carriages,
// like engines, maintenance carriages, etc… as they provide valuable
// information to passengers about where to stand on a platform.
// This message/field is still experimental, and subject to change. It may be formally adopted in the future.
repeated CarriageDetails multi_carriage_details = 11;
// The extensions namespace allows 3rd-party developers to extend the
// GTFS Realtime Specification in order to add and evaluate new features and
// modifications to the spec.
extensions 1000 to 1999;
// The following extension IDs are reserved for private use by any organization.
extensions 9000 to 9999;
}
// An alert, indicating some sort of incident in the public transit network.
message Alert {
// 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 TimeRange active_period = 1;
// Entities whose users we should notify of this alert.
repeated EntitySelector informed_entity = 5;
// Cause of this alert. If cause_detail is included, then Cause must also be included.
enum Cause {
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;
}
optional Cause cause = 6 [default = UNKNOWN_CAUSE];
// What is the effect of this problem on the affected entity. If effect_detail is included, then Effect must also be included.
enum Effect {
NO_SERVICE = 1;
REDUCED_SERVICE = 2;
// 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.
SIGNIFICANT_DELAYS = 3;
DETOUR = 4;
ADDITIONAL_SERVICE = 5;
MODIFIED_SERVICE = 6;
OTHER_EFFECT = 7;
UNKNOWN_EFFECT = 8;
STOP_MOVED = 9;
NO_EFFECT = 10;
ACCESSIBILITY_ISSUE = 11;
}
optional Effect effect = 7 [default = UNKNOWN_EFFECT];
// The URL which provides additional information about the alert.
optional TranslatedString url = 8;
// Alert header. Contains a short summary of the alert text as plain-text.
optional TranslatedString header_text = 10;
// Full description for the alert as plain-text. The information in the
// description should add to the information of the header.
optional TranslatedString description_text = 11;
// Text for alert header to be used in text-to-speech implementations. This field is the text-to-speech version of header_text.
optional TranslatedString tts_header_text = 12;
// Text for full description for the alert to be used in text-to-speech implementations. This field is the text-to-speech version of description_text.
optional TranslatedString tts_description_text = 13;
// Severity of this alert.
enum SeverityLevel {
UNKNOWN_SEVERITY = 1;
INFO = 2;
WARNING = 3;
SEVERE = 4;
}
optional SeverityLevel severity_level = 14 [default = UNKNOWN_SEVERITY];
// TranslatedImage to be displayed along the alert text. Used to explain visually the alert effect of a detour, station closure, etc. The image must enhance the understanding of the alert. Any essential information communicated within the image must also be contained in the alert text.
// The following types of images are discouraged : image containing mainly text, marketing or branded images that add no additional information.
// NOTE: This field is still experimental, and subject to change. It may be formally adopted in the future.
optional TranslatedImage image = 15;
// Text describing the appearance of the linked image in the `image` field (e.g., in case the image can't be displayed
// or the user can't see the image for accessibility reasons). See the HTML spec for alt image text - https://html.spec.whatwg.org/#alt.
// NOTE: This field is still experimental, and subject to change. It may be formally adopted in the future.
optional TranslatedString image_alternative_text = 16;
// Description of the cause of the alert that allows for agency-specific language; more specific than the Cause. If cause_detail is included, then Cause must also be included.
// NOTE: This field is still experimental, and subject to change. It may be formally adopted in the future.
optional TranslatedString cause_detail = 17;
// Description of the effect of the alert that allows for agency-specific language; more specific than the Effect. If effect_detail is included, then Effect must also be included.
// NOTE: This field is still experimental, and subject to change. It may be formally adopted in the future.
optional TranslatedString effect_detail = 18;
// The extensions namespace allows 3rd-party developers to extend the
// GTFS Realtime Specification in order to add and evaluate new features
// and modifications to the spec.
extensions 1000 to 1999;
// The following extension IDs are reserved for private use by any organization.
extensions 9000 to 9999;
}
//
// Low level data structures used above.
//
// 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.
message TimeRange {
// 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 start = 1;
// 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.
optional uint64 end = 2;
// The extensions namespace allows 3rd-party developers to extend the
// GTFS Realtime Specification in order to add and evaluate new features and
// modifications to the spec.
extensions 1000 to 1999;
// The following extension IDs are reserved for private use by any organization.
extensions 9000 to 9999;
}
// A position.
message Position {
// Degrees North, in the WGS-84 coordinate system.
required float latitude = 1;
// Degrees East, in the WGS-84 coordinate system.
required float longitude = 2;
// 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 float bearing = 3;
// Odometer value, in meters.
optional double odometer = 4;
// Momentary speed measured by the vehicle, in meters per second.
optional float speed = 5;
// The extensions namespace allows 3rd-party developers to extend the
// GTFS Realtime Specification in order to add and evaluate new features and
// modifications to the spec.
extensions 1000 to 1999;
// The following extension IDs are reserved for private use by any organization.
extensions 9000 to 9999;
}
// 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.
message TripDescriptor {
// 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. When schedule_relationship is DUPLICATED within a TripUpdate, the trip_id identifies the trip from
// static GTFS to be duplicated. When schedule_relationship is DUPLICATED within a VehiclePosition, the trip_id
// identifies the new duplicate trip and must contain the value for the corresponding TripUpdate.TripProperties.trip_id.
optional string trip_id = 1;
// The route_id from the GTFS that this selector refers to.
optional string route_id = 5;
// The direction_id from the GTFS feed trips.txt file, indicating the
// direction of travel for trips this selector refers to.
optional uint32 direction_id = 6;
// 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_time = 2;
// 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 string start_date = 3;
// 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.
enum ScheduleRelationship {
// Trip that is running in accordance with its GTFS schedule, or is close
// enough to the scheduled trip to be associated with it.
SCHEDULED = 0;
// 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.
// NOTE: Currently, behavior is unspecified for feeds that use this mode. There are discussions on the GTFS GitHub
// [(1)](https://github.com/google/transit/issues/106) [(2)](https://github.com/google/transit/pull/221)
// [(3)](https://github.com/google/transit/pull/219) around fully specifying or deprecating ADDED trips and the
// documentation will be updated when those discussions are finalized.
ADDED = 1;
// A trip that is running with no schedule associated to it (GTFS frequencies.txt exact_times=0).
// Trips with ScheduleRelationship=UNSCHEDULED must also set all StopTimeUpdates.ScheduleRelationship=UNSCHEDULED.
UNSCHEDULED = 2;
// A trip that existed in the schedule but was removed.
CANCELED = 3;
// Should not be used - for backwards-compatibility only.
REPLACEMENT = 5 [deprecated = true];
// 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. Used with TripUpdate.TripProperties.trip_id, TripUpdate.TripProperties.start_date,
// and TripUpdate.TripProperties.start_time to copy an existing trip from static GTFS but start at a different service
// date and/or time. Duplicating a trip is allowed if the service related to the original trip in (CSV) GTFS
// (in calendar.txt or calendar_dates.txt) is operating within the next 30 days. The trip to be duplicated is
// identified via TripUpdate.TripDescriptor.trip_id. This enumeration does not modify the existing trip referenced by
// TripUpdate.TripDescriptor.trip_id - if a producer wants to cancel the original trip, it must publish a separate
// TripUpdate with the value of CANCELED or DELETED. Trips defined in GTFS frequencies.txt with exact_times that is
// empty or equal to 0 cannot be duplicated. The VehiclePosition.TripDescriptor.trip_id for the new trip must contain
// the matching value from TripUpdate.TripProperties.trip_id and VehiclePosition.TripDescriptor.ScheduleRelationship
// must also be set to DUPLICATED.
// Existing producers and consumers that were using the ADDED enumeration to represent duplicated trips must follow
// the migration guide (https://github.com/google/transit/tree/master/gtfs-realtime/spec/en/examples/migration-duplicated.md)
// to transition to the DUPLICATED enumeration.
// NOTE: This field is still experimental, and subject to change. It may be formally adopted in the future.
DUPLICATED = 6;
// A trip that existed in the schedule but was removed and must not be shown to users.
// DELETED should be used instead of CANCELED to indicate that a transit provider would like to entirely remove
// information about the corresponding trip from consuming applications, so the trip is not shown as cancelled to
// riders, e.g. a trip that is entirely being replaced by another trip.
// This designation becomes particularly important if several trips are cancelled and replaced with substitute service.
// If consumers were to show explicit information about the cancellations it would distract from the more important
// real-time predictions.
// NOTE: This field is still experimental, and subject to change. It may be formally adopted in the future.
DELETED = 7;
}
optional ScheduleRelationship schedule_relationship = 4;
message ModifiedTripSelector {
// The 'id' from the FeedEntity in which the contained TripModifications object affects this trip.
optional string modifications_id = 1;
// The trip_id from the GTFS feed that is modified by the modifications_id
optional string affected_trip_id = 2;
// The initially scheduled start time of this trip instance, applied to the frequency based modified trip. Same definition as start_time in TripDescriptor.
optional string start_time = 3;
// The start date of this trip instance in YYYYMMDD format, applied to the modified trip. Same definition as start_date in TripDescriptor.
optional string start_date = 4;
// The extensions namespace allows 3rd-party developers to extend the
// GTFS Realtime Specification in order to add and evaluate new features and
// modifications to the spec.
extensions 1000 to 1999;
// The following extension IDs are reserved for private use by any organization.
extensions 9000 to 9999;
}
// Linkage to any modifications done to this trip (shape changes, removal or addition of stops).
// If this field is provided, the `trip_id`, `route_id`, `direction_id`, `start_time`, `start_date` fields of the `TripDescriptor` MUST be left empty, to avoid confusion by consumers that aren't looking for the `ModifiedTripSelector` value.
optional ModifiedTripSelector modified_trip = 7;
// The extensions namespace allows 3rd-party developers to extend the
// GTFS Realtime Specification in order to add and evaluate new features and
// modifications to the spec.
extensions 1000 to 1999;
// The following extension IDs are reserved for private use by any organization.
extensions 9000 to 9999;
}
// Identification information for the vehicle performing the trip.
message VehicleDescriptor {
// 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 id = 1;
// User visible label, i.e., something that must be shown to the passenger to
// help identify the correct vehicle.
optional string label = 2;
// The license plate of the vehicle.
optional string license_plate = 3;
enum WheelchairAccessible {
// The trip doesn't have information about wheelchair accessibility.
// This is the **default** behavior. If the static GTFS contains a
// _wheelchair_accessible_ value, it won't be overwritten.
NO_VALUE = 0;
// The trip has no accessibility value present.
// This value will overwrite the value from the GTFS.
UNKNOWN = 1;
// The trip is wheelchair accessible.
// This value will overwrite the value from the GTFS.
WHEELCHAIR_ACCESSIBLE = 2;
// The trip is **not** wheelchair accessible.
// This value will overwrite the value from the GTFS.
WHEELCHAIR_INACCESSIBLE = 3;
}
optional WheelchairAccessible wheelchair_accessible = 4 [default = NO_VALUE];
// The extensions namespace allows 3rd-party developers to extend the
// GTFS Realtime Specification in order to add and evaluate new features and
// modifications to the spec.
extensions 1000 to 1999;
// The following extension IDs are reserved for private use by any organization.
extensions 9000 to 9999;
}
// A selector for an entity in a GTFS feed.
message EntitySelector {
// 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 agency_id = 1;
optional string route_id = 2;
// corresponds to route_type in GTFS.
optional int32 route_type = 3;
optional TripDescriptor trip = 4;
optional string stop_id = 5;
// Corresponds to trip direction_id in GTFS trips.txt. If provided the
// route_id must also be provided.
optional uint32 direction_id = 6;
// The extensions namespace allows 3rd-party developers to extend the
// GTFS Realtime Specification in order to add and evaluate new features and
// modifications to the spec.
extensions 1000 to 1999;
// The following extension IDs are reserved for private use by any organization.
extensions 9000 to 9999;
}
// 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.
message TranslatedString {
message Translation {
// A UTF-8 string containing the message.
required string text = 1;
// 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.
optional string language = 2;
// The extensions namespace allows 3rd-party developers to extend the
// GTFS Realtime Specification in order to add and evaluate new features and
// modifications to the spec.
extensions 1000 to 1999;
// The following extension IDs are reserved for private use by any organization.
extensions 9000 to 9999;
}
// At least one translation must be provided.
repeated Translation translation = 1;
// The extensions namespace allows 3rd-party developers to extend the
// GTFS Realtime Specification in order to add and evaluate new features and
// modifications to the spec.
extensions 1000 to 1999;
// The following extension IDs are reserved for private use by any organization.
extensions 9000 to 9999;
}
// An internationalized image containing per-language versions of a URL linking to an image
// along with meta information
// Only one of the images from a message will be retained by consumers. 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.
// NOTE: This field is still experimental, and subject to change. It may be formally adopted in the future.
message TranslatedImage {
message LocalizedImage {
// String containing an URL linking to an image
// The image linked must be less than 2MB.
// If an image changes in a significant enough way that an update is required on the consumer side, the producer must update the URL to a new one.
// The URL should be a fully qualified URL that includes http:// or https://, and any special characters in the URL must be correctly escaped. See the following http://www.w3.org/Addressing/URL/4_URI_Recommentations.html for a description of how to create fully qualified URL values.
required string url = 1;
// IANA media type as to specify the type of image to be displayed.
// The type must start with "image/"
required string media_type = 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.
optional string language = 3;
// The extensions namespace allows 3rd-party developers to extend the
// GTFS Realtime Specification in order to add and evaluate new features and
// modifications to the spec.
extensions 1000 to 1999;
// The following extension IDs are reserved for private use by any organization.
extensions 9000 to 9999;
}
// At least one localized image must be provided.
repeated LocalizedImage localized_image = 1;
// The extensions namespace allows 3rd-party developers to extend the
// GTFS Realtime Specification in order to add and evaluate new features and
// modifications to the spec.
extensions 1000 to 1999;
// The following extension IDs are reserved for private use by any organization.
extensions 9000 to 9999;
}
// Describes the physical path that a vehicle takes when it's not part of the (CSV) GTFS,
// such as for a detour. Shapes belong to Trips, and consist of a sequence of shape points.
// Tracing the points in order provides the path of the vehicle. Shapes do not need to intercept
// the location of Stops exactly, but all Stops on a trip should lie within a small distance of
// the shape for that trip, i.e. close to straight line segments connecting the shape points
// NOTE: This message is still experimental, and subject to change. It may be formally adopted in the future.
message Shape {
// Identifier of the shape. Must be different than any shape_id defined in the (CSV) GTFS.
// This field is required as per reference.md, but needs to be specified here optional because "Required is Forever"
// See https://developers.google.com/protocol-buffers/docs/proto#specifying_field_rules
// NOTE: This field is still experimental, and subject to change. It may be formally adopted in the future.
optional string shape_id = 1;
// Encoded polyline representation of the shape. This polyline must contain at least two points.
// For more information about encoded polylines, see https://developers.google.com/maps/documentation/utilities/polylinealgorithm
// This field is required as per reference.md, but needs to be specified here optional because "Required is Forever"
// See https://developers.google.com/protocol-buffers/docs/proto#specifying_field_rules
// NOTE: This field is still experimental, and subject to change. It may be formally adopted in the future.
optional string encoded_polyline = 2;
// The extensions namespace allows 3rd-party developers to extend the
// GTFS Realtime Specification in order to add and evaluate new features and
// modifications to the spec.
extensions 1000 to 1999;
// The following extension IDs are reserved for private use by any organization.
extensions 9000 to 9999;
}
// Describes a stop which is served by trips. All fields are as described in the GTFS-Static specification.
// NOTE: This message is still experimental, and subject to change. It may be formally adopted in the future.
message Stop {
enum WheelchairBoarding {
UNKNOWN = 0;
AVAILABLE = 1;
NOT_AVAILABLE = 2;
}
optional string stop_id = 1;
optional TranslatedString stop_code = 2;
optional TranslatedString stop_name = 3;
optional TranslatedString tts_stop_name = 4;
optional TranslatedString stop_desc = 5;
optional float stop_lat = 6;
optional float stop_lon = 7;
optional string zone_id = 8;
optional TranslatedString stop_url = 9;
optional string parent_station = 11;
optional string stop_timezone = 12;
optional WheelchairBoarding wheelchair_boarding = 13 [default = UNKNOWN];
optional string level_id = 14;
optional TranslatedString platform_code = 15;
// The extensions namespace allows 3rd-party developers to extend the
// GTFS Realtime Specification in order to add and evaluate new features and
// modifications to the spec.
extensions 1000 to 1999;
// The following extension IDs are reserved for private use by any organization.
extensions 9000 to 9999;
}
// NOTE: This field is still experimental, and subject to change. It may be formally adopted in the future.
message TripModifications {
// A `Modification` message replaces a span of n stop times from each affected trip starting at `start_stop_selector`.
message Modification {
// The stop selector of the first stop_time of the original trip that is to be affected by this modification.
// Used in conjuction with `end_stop_selector`.
// `start_stop_selector` is required and is used to define the reference stop used with `travel_time_to_stop`.
optional StopSelector start_stop_selector = 1;
// The stop selector of the last stop of the original trip that is to be affected by this modification.
// The selection is inclusive, so if only one stop_time is replaced by that modification, `start_stop_selector` and `end_stop_selector` must be equivalent.
// If no stop_time is replaced, `end_stop_selector` must not be provided. It's otherwise required.
optional StopSelector end_stop_selector = 2;
// The number of seconds of delay to add to all departure and arrival times following the end of this modification.
// If multiple modifications apply to the same trip, the delays accumulate as the trip advances.
optional int32 propagated_modification_delay = 3 [default = 0];
// A list of replacement stops, replacing those of the original trip.
// The length of the new stop times may be less, the same, or greater than the number of replaced stop times.
repeated ReplacementStop replacement_stops = 4;
// An `id` value from the `FeedEntity` message that contains the `Alert` describing this Modification for user-facing communication.
optional string service_alert_id = 5;
// This timestamp identifies the moment when the modification has last been changed.
// In POSIX time (i.e., number of seconds since January 1st 1970 00:00:00 UTC).
optional uint64 last_modified_time = 6;
// The extensions namespace allows 3rd-party developers to extend the
// GTFS Realtime Specification in order to add and evaluate new features and
// modifications to the spec.
extensions 1000 to 1999;
// The following extension IDs are reserved for private use by any organization.
extensions 9000 to 9999;
}
message SelectedTrips {
// A list of trips affected with this replacement that all have the same new `shape_id`.
repeated string trip_ids = 1;
// The ID of the new shape for the modified trips in this SelectedTrips.
// May refer to a new shape added using a GTFS-RT Shape message, or to an existing shape defined in the GTFS-Static feed’s shapes.txt.
optional string shape_id = 2;
// The extensions namespace allows 3rd-party developers to extend the
// GTFS Realtime Specification in order to add and evaluate new features and
// modifications to the spec.
extensions 1000 to 1999;
// The following extension IDs are reserved for private use by any organization.
extensions 9000 to 9999;
}
// A list of selected trips affected by this TripModifications.
repeated SelectedTrips selected_trips = 1;
// A list of start times in the real-time trip descriptor for the trip_id defined in trip_ids.
// Useful to target multiple departures of a trip_id in a frequency-based trip.
repeated string start_times = 2;
// Dates on which the modifications occurs, in the YYYYMMDD format. Producers SHOULD only transmit detours occurring within the next week.
// The dates provided should not be used as user-facing information, if a user-facing start and end date needs to be provided, they can be provided in the linked service alert with `service_alert_id`
repeated string service_dates = 3;
// A list of modifications to apply to the affected trips.
repeated Modification modifications = 4;
// The extensions namespace allows 3rd-party developers to extend the
// GTFS Realtime Specification in order to add and evaluate new features and
// modifications to the spec.
extensions 1000 to 1999;
// The following extension IDs are reserved for private use by any organization.
extensions 9000 to 9999;
}
// NOTE: This field is still experimental, and subject to change. It may be formally adopted in the future.
// Select a stop by stop sequence or by stop_id. At least one of the two values must be provided.
message StopSelector {
// Must be the same as in stop_times.txt in the corresponding GTFS feed.
optional uint32 stop_sequence = 1;
// Must be the same as in stops.txt in the corresponding GTFS feed.
optional string stop_id = 2;
// The extensions namespace allows 3rd-party developers to extend the
// GTFS Realtime Specification in order to add and evaluate new features and
// modifications to the spec.
extensions 1000 to 1999;
// The following extension IDs are reserved for private use by any organization.
extensions 9000 to 9999;
}
// NOTE: This field is still experimental, and subject to change. It may be formally adopted in the future.
message ReplacementStop {
// The difference in seconds between the arrival time at this stop and the arrival time at the reference stop. The reference stop is the stop prior to start_stop_selector. If the modification begins at the first stop of the trip, then the first stop of the trip is the reference stop.
// This value MUST be monotonically increasing and may only be a negative number if the first stop of the original trip is the reference stop.
optional int32 travel_time_to_stop = 1;
// The replacement stop ID which will now be visited by the trip. May refer to a new stop added using a GTFS-RT Stop message, or to an existing stop defined in the GTFS-Static feed’s stops.txt. The stop MUST have location_type=0 (routable stops).
optional string stop_id = 2;
// The extensions namespace allows 3rd-party developers to extend the
// GTFS Realtime Specification in order to add and evaluate new features and
// modifications to the spec.
extensions 1000 to 1999;
// The following extension IDs are reserved for private use by any organization.
extensions 9000 to 9999;
}