I am in the middle of the single player game, and liking it.

but the further I get into the game, the more I wonder about the name.

Rage.

not really sure why they named it that. I mean, it is a post apocalyptic world, people are not exactly happy, but...Rage?

I'm guessing the driving aspect, road .

Never rea;lly got it myself. I guess they like their one word titles. Wolfenstein, Quake, Doom and now RAGE. Guess it fits the feel, in fact now Wolfenstein seems to be the odd name out. All the others are feelings and sensations.

Lol woah... I actually think http://www.gamesas.com/user/720099-envoidnul/ is totally right, I would guess it's called RAGE because of the 'road rage' you express in the driving aspect throughout.
After all, the first thing they imagined with idTech5 was a wasteland with vehicles racing and crashing through it. Saw it in one of the old documentary videos.

that makes a lot of sense. I second that theory.