PassingEvent¶

Status¶

Normative

Definition¶

A PassingEvent represents the operational event of a vehicle journey passing, arriving at, or departing from a PublicTransportStop.

It is an operational event associated with the execution of a MonitoredVehicleJourney.

A PassingEvent represents the occurrence itself.

Scheduled, predicted, and observed times describe different temporal aspects of the same event rather than different semantic concepts.

Identity¶

The semantic identity of a PassingEvent is established by:

the associated MonitoredVehicleJourney;
the PublicTransportStop;
the operational event type.

Changes to scheduled, predicted, or observed times do not alter the identity of the PassingEvent.

They update the temporal properties of the same event.

Where the same MonitoredVehicleJourney visits the same PublicTransportStop more than once, occurrence identity shall additionally include a stop sequence, PointInJourneyPattern, or another profile-defined discriminator.

Motivation¶

Public transport systems publish multiple time values describing the same operational event.

Examples include:

scheduled arrival;
predicted arrival;
observed arrival;
scheduled departure;
predicted departure;
observed departure.

Although these values may differ, they all refer to the same operational event.

SCRA therefore models the event itself rather than individual timestamps.

Characteristics¶

A PassingEvent:

belongs to one MonitoredVehicleJourney;
refers to one PublicTransportStop;
represents one operational event;
may contain scheduled, predicted, and observed times;
may be updated repeatedly as operational information changes.

Relationships¶

MonitoredVehicleJourney¶

Each PassingEvent belongs to one MonitoredVehicleJourney.

The monitored journey provides the operational context of the event.

PublicTransportStop¶

Each PassingEvent refers to one PublicTransportStop.

The stop defines where the operational event occurs.

Typical Properties¶

Typical semantic properties include:

eventType
scheduledTime
predictedTime
observedTime
predictionConfidence
observationTimestamp
delay
minutesUntilArrival
referenceTime

The normative SCRA vocabulary terms above define the compact property names used by conforming NGSI-LD representations.

Conformance Requirements¶

A conforming PassingEvent shall include:

one monitoredVehicleJourney Relationship;
one stop Relationship;
one eventType Property.

A conforming PassingEvent shall include at least one of:

scheduledTime;
predictedTime;
observedTime.

The following conditional requirements apply:

minutesUntilArrival shall be accompanied by referenceTime;
predictionConfidence shall be used only when a predicted operational value such as predictedTime is present;
delay shall be accompanied by the operational and baseline time values required by the normative delay calculation rules;
observationTimestamp shall describe the observation or report supporting the operational information and shall not replace observedTime.

The following properties are optional unless made mandatory by an applicable profile:

predictionConfidence;
observationTimestamp;
delay;
minutesUntilArrival;
referenceTime, except when required by minutesUntilArrival.

Origin¶

This semantic concept harmonizes several existing concepts, including:

Transmodel — Passing Time
GTFS Stop Time
GTFS-Realtime StopTimeUpdate
SIRI Estimated Call
SIRI Monitored Call

SCRA models the operational event itself as the canonical semantic concept.

Mapping Guidance¶

Typical mappings include:

Source	Semantic Mapping
GTFS StopTime	PassingEvent
GTFS-Realtime StopTimeUpdate	PassingEvent
SIRI EstimatedCall	PassingEvent
SIRI MonitoredCall	PassingEvent

Mappings are informative and do not modify the semantic definition.