Peter Yeah, those are active, and so is the subforum for Stunt Rally. However, the subforums under "Other Project Forums" seem to be almost completely dead (there's some recent-ish posts, but they're from late last year) and some of those subforums are, in fact, locked.
Admittedly, it seems that the old forum has never really been the most active of communities since it seems the record for most users online is 208, and that was back in 2010.
(EDIT: Changed an instance of "forums" to "subforums" to maintain consistent terminology, and fixed a typo.)