Fighting games were always and probably will always be a hit on Arcade machines, with games like Tekken and Street Fighter. Though Street Fighter IV can be played on Arcade, Super Street Fighter IV will also be playable on Arcades.
It was announced by Ono in the following video (skip to 2:30):
You can here the guy say “Super Street Fighter IV” along with the word “Arcade”.
And if you are still not convinced, here is an official word with an estimated release date as well – “Everyone heard the news, right? We’re expecting SSF4 release to be July/August…”