RoR has a physics system capable of applying flexibility on the wheels and chassis in real time accurately. This feature allows RoR to offer a better performance of the vehicles when running and they can be deformed while being driven by you. Be careful, If you crash into a wall or piece of terrain, the vehicle can be permanently deformed in a very realistic way.
Nowadays, Rigs of Rods offers more than 1700 different vehicles and you can drive all of them, just check the list in the Official Site.
Finally, it supports force feedback joysticks and wheels.
Pentium 4 or equivalent
512 MB RAM
128 MB video and DirectX 9c.