Why "departed" means three different things in three modes, and the model we built so your systems only need to know one.
An airline says departed when the wheels lift. A shipping line says it when the vessel leaves the berth, which can be hours before it clears the port. A trucker's phone says it when the app was tapped.
We rebuilt tracking around milestones that mean the same thing everywhere: picked up, handed to carrier, left origin country, arrived destination country, released, delivered. Mode-specific detail hangs off each milestone, but the spine never changes.
Customers who integrate once get every mode. Our own control tower works the same way: an exception is an exception, whether it is a missed connection in Dubai or a flat tyre outside Ghent.