Later on you hit another track there with two of those areas. Get used to it. :P
Like was said, you should be able to veer left and right but it's not exact and I still hit rocks all the time.
I messed with settings more and it seems to work better? It was very strange, but I feel like messing with the video settings did something. I really could not steer left/right before, now I can a little.
A little is the best you're going to do. You are supposed to have very limited movement in those areas. Like I said, I've played the game countless hours, winning every track with every pod, and I still run into shit on those parts.
My best suggestion is make sure you build up a good lead so you can afford the occasional collision without being passed.