The entrance/exit on a passenger vehicle (e.g., bus or train) used for boarding and alighting.
バスの乗降口は前方にありますのでご注意ください。
Please note that the bus entrance/exit is at the front.
混雑時は乗降口付近での会話は控えてください。
Please refrain from talking near the entrance/exit when it's crowded.
この車両は乗降口が狭いので、荷物に注意してください。
This car's entrance/exit is narrow, so please mind your luggage.