What is a transit?

A transit is one vessel passing through a chokepoint, in either direction. If a ship enters the Suez Canal at one end and leaves at the other, that is one transit.

Transits and port calls

Ports and chokepoints are counted differently. A port is a place ships stop, so we count calls. A chokepoint is a place ships pass through, so we count transits. The two are not comparable as numbers, and we never add them together.

Reading a change

If daily transits at a chokepoint fall for a week, several things could explain it: an incident there, ships choosing another route, a holiday, or ordinary variation between weekdays and weekends. Our effect method compares a disruption window with a baseline built from the weeks before it, using the same weekdays and leaving out holidays and other recorded events. It shows timing, not cause.

See the chokepoints we cover.