Car go through the floor

Hi, I’ve made my car rig following this tutorials:


and I want to make something like this:

But when I set my keyframes and play animation car just go through the hill.
First keyframe is in front of hill and second one is behind it.So car should go up the hill and then down to reach it’s final kexframed location.
Can you tell me how to solve this and am I doing something wrong.

Thanks in advance!

This is a very good question. I have seen this done with blender before, using a rig, but I cannot recall the thread. If you search the forum you may find it.
(edit) I found this…have not seen roubal around lately though… http://blenderartists.org/forum/archive/index.php/t-169146.html
http://vimeo.com/7047834

there’s also this video which is helpful…http://www.youtube.com/watch?v=EyARunD9Rco