OK, so we have a bus station where *all* motor vehicles have a legal right to drive?

If you ever take and pass your driving theory test, you will hopefully have learned that a no entry sign (TSRGD diagram 616) with a plate below stating "except buses" means that no vehicle may enter except a bus.

In OSM, this is tagged as:
vehicle=no + bus=yes
No other access tags are required.

You do not need to add bicycle=no because bicycles are vehicles. You certainly do not need to add horse=no or motor_vehicle=yes because both of those statements are provably false.

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