[landedgentry]

The MIFARE protocol (which Oyster cards use) takes 300ms to 500ms per tap. EMV (i.e. contactless cards) take ~500ms, which slows down normal walking speed.

Here's a good summary of NFC protocols used for transit gates: https://atadistance.net/2020/06/13/transit-gate-evolution-wh...

The Felica standard is fastest at 100ms per tap, and is used in Japan (e.g. Suica card) and Hong Kong (Octopus card).