The rocks should be able to move around instead of being fixed to the map. At the moment they totally rip the car apart if you hit a tiny rock for example by sliding at a curve and a wheel hits a small stone on the side of the road).
Should be possible to make a Jbeam for a rock, I guess they haven't put it as it could have been a pain for older pc. Anyway, upgrade your forum account (as you are talking of rocks I suppose you bought the game). The link is in the email with the serial, you get the Drive badge under the avatar when you do that, plus the access to the whole forum.
I don't have the full game. Got no credit card yet lol. I've been watching lots and lots and lots of videos and noticed this problem. And the tech demo map has lots of small rocks too.
I bet you got paypal or a bank cheque? bank cheque is for wire transfer will cost you more. paypal is debit card I think. Anyways I got credit card but I have to wait for my father to buy for me. *UPDATE(sorry for going off-topic)* Rocks are not necessary that they move when you nudge the rocks cause rocks are heavy and your wheels are round unless the rocks are on a edge then it will topple because of the of 1 side is heavier... so most rocks will not move only maybe 25% of rocks will move and wont deform.