乗降 じょうこう しゃ優先 ゆうせんでしょう
jōkōsha yūsendeshō

Noun
Desu Copula

Expresses probability in a polite manner ("probably…") of 乗降車優先

1. Probably boarding/alighting passengers first.; Priority to vehicles boarding/alighting.

Polite
Presumptive
Conjecture