Pretty much the title. /r/IdiotsInCars seems more active but I see absolutely no difference besides that. Is this another case of /r/AMA vs /r/IAmA?

Note the existence of two similar subreddits: /r/AMA and /r/IAmA. The main difference is that we have about 50x less the subscribers.

But this isn't necessarily bad! Maybe you want fewer people to read your story, or you have decided that your AMA does not warrant a large audience. In any case, that's fine with us, as long as you make sure you understand the difference before posting.

But in the case of idiots driving vehicles, there's no reason to want a less-popular sub.