I did a search and haven't found the problem being addressed on this forum, so I thought I'd notify all the people here. As it is a bug appearing specifically in Project Reality I'm posting it here. Some might be spending most (if not all) of their time on this forum and not the one over at realitymod.com like myself

Anyone else noticed how their perspective suddenly and unexpectedly starts to get thrown around a LOT when doing turns in vehicles like the Vodnik, Humvee etc? I did one day and nearly felt sick after driving around just a little bit. EVERY TIME you make the slightest change of direction, the screen shakes to one side enough to make you dizzy.
It's like the small tilt that your screen should do when maneuvering the vehicle to the left or right is increased to 45 degrees or something!
Quite irritating, especially when doing some fine driving that requires a lot of keys being pressed in order to do small adjustments.
Well I searched the official PR Bugs Forum and I believe I've found the solution.
Original topic:
http://www.realitymod.com/forum/f26-...-vehicles.html

CAUSE: The controls.con file was edited by Forgotten Hope 2 (!) upon install and maybe running it just one time. So if you're like me and unfortunate enough to have this bug starting to haunt you, please read on.

REMEDY: Delete these 2 lines in the controls.con of your profile and set a write protection before you start FH2 again. you might have to do this several times in the .con file.
- Yes, Forgotten Hope 2 edited something which causes problems while you play PR! Ain't that something? Removing all instances of these in the controls.con will make your driving normal again.

ControlMap.addAxisToAxisMapping c_PIPitch IDFMouse IDAxis_1 0 0
ControlMap.addAxisToAxisMapping c_PIRoll IDFMouse IDAxis_0 0 0

(Thanks to: l|Bubba|l )