The SIRI SituationExchangeDelivery element only appears when there is a service alert active for a route or stop being called on. It is used by the responses to both the VehicleMonitoring and StopMonitoring calls.
The XML below illustrates the SIRI SituationExchangeDelivery element.
<SituationExchangeDelivery>
<Situations>
<! One each per Service Alert->
<PtSituationElement>
<! Unique ID->
<SituationNumber>MTA NYCT_8d065d76-2813-46ee-b024-20f956232831</SituationNumber>
<! Information on temporal applicability of the service alert->
<PublicationWindow>
<! Start time of Service Alert->
<StartTime>2011-12-12T08:45:00-05:00</StartTime>
<! End time of Service Alert>
<EndTime>2011-12-13T08:45:00-05:00</StartTime>
</PublicationWindow>
<! Severity of the event>
<Severity>undefined</Severity>
<! Summary text>
<Summary xml:lang="EN">The B63 is having a party!</Summary>
<! Long description Text>
<Description xml:lang="EN">The B63 is having a party! (SMS)</Description>
<Affects>
<! Element containing VehicleJourney lines and directions>
<VehicleJourneys>
<! One for each Line/Direction>
<AffectedVehicleJourney>
<! GTFS Route_ID, prefixed by agency_id>
<LineRef>MTA NYCT_B63</LineRef>
<! GTFS Route direction_id >
<DirectionRef>1</DirectionRef>
</AffectedVehicleJourney>
<AffectedVehicleJourney>
<LineRef>MTA NYCT_B63</LineRef>
<! GTFS Opposite Route direction_id >
<DirectionRef>0</DirectionRef>
</AffectedVehicleJourney>
</VehicleJourneys>
</Affects>
<Consequences>
<Consequence>
<! Service alert consequence: CANCELLED, NO_SERVICE, DISRUPTED, INTERMITTENT_SERVICE, DELAYED, DIVERTED etc>
<Condition>altered</Condition>
</Consequence>
</Consequences>
</PtSituationElement>
</Situations>
</SituationExchangeDelivery>
</ServiceDelivery>
