In issue 770 of the Sea‑Intelligence Sunday Spotlight, we analysed the relationship between structural schedule buffering and early vessel arrivals.
Shipping lines are increasingly relying on schedule buffers, which involve increasing transit times, to manage ongoing network disruptions. A direct byproduct of this operational strategy is an elevated volume of early vessel arrivals. These early arrivals introduce “negative delay” into the global average vessel delay metric, which softens the reported severity of delays and obscures the true magnitude of network friction.
To measure this impact, we evaluate the Schedule Padding Index (SPI) alongside the total number of early arrivals. A negative SPI value indicates the artificial addition of schedule buffers, which corresponds directly with a relatively higher number of early vessel arrivals.
During the pre‑pandemic baseline spanning 2012‑2019, the global SPI averaged +0.06 days. During this time‑period, early arrivals represented a mere 1.9% of global deep‑sea traffic, averaging 219 vessels per month. This dynamic shifted dramatically during the pandemic recovery in 2022, where the yearly average SPI plummeted to ‑0.20 days and early arrivals skyrocketed to an average of 716 vessels per month, representing 6.9% of all global arrivals. (....)