Public Transport ETA can generate automatic transfer alerts. Three use cases are considered:
-
Trip-Trip transfer alerts
The system estimates the time to accomplish the transfer between two trips (trip_from, trip_to) at defined public stops (public_stop_from, public_stop_to).
-
Trip-route transfer alerts
The system estimates the time to accomplish the transfer between a trip (trip_from) and a route (route_to) at defined public stops (public_stop_from, public_stop_to).
-
Route-route transfer alerts
The system evaluates the time to accomplish the transfer between two routes (route_from, route_to) at defined public stops (public_stop_from, public_stop_to).
The time to accomplish a transfer is the amount of time from the request instant (timestamp) to the time the passenger boards on trip_to at stop_to.
An alert is raised when the following condition is satisfied:
The system raises an alert if, according to the real-time information, the time instant at which the passengers accomplish the transfer is delayed beyond the specified threshold 
compared to the original schedule:
The last relation resolves the alert condition:
| Variable | Description |
|---|---|
|
|
Amount of time until transfer is accomplished according to the planned schedule, measured in seconds. |
|
|
Amount of time until transfer is accomplished according to the real-time information, measured in seconds. |
|
|
Alert threshold |
|
|
Minimum amount of time to move from public_stop_from to public_stop_to. |
|
|
Amount of time from request instant timestamp until the next arrival of the trip_from at stop_from. If the request is for a route_from, trip_from is the first upcoming trip for the route_from. |
|
|
Amount of time to the next arrival of trip_to at stop_to after the time instant given by:
If the request is for a route_to, trip_to is the first upcoming trip for the route_to, after such instant. |
|
|
Arrival time instant of trip_from at stop_from. |
|
|
Arrival time instant of trip_to at stop_to, according to the real-time information. |
|
|
Arrival time instant of trip_to at stop_to, according to the planned schedule. |
The services are made available externally by dedicated APIs (→ Public transport API).