副詞と形容詞の使い方について・誰かが英語の使い方に注意した方が良い。

I can't say who has to be careful, since it isn't clear to me from my photo. Does it say the train company in the bottom right corner?

Anyway, the sign says:

× Smoothly and Speedy

◯ Smoothly and Speedily (better)

◯ Smooth and Speedy (best)

When you want to use two words that describe something and connect them with a conjunction, they need to be of the same type.

• conjunction - 接続詞

The problem here is that "smoothly" is an adverb and "speedy" is an adjective. The hint here is that "ly" usually signifies an adverb, while "y" alone is usually an adjective.

I hope your holiday journeys are smooth and speedy.