Object rotate according to terrain

Is there any simple way to rotate an object depending on if its on a hill or ramp on a terrain.
Like a bike riding up a hill rotates, or a sled going down a hill.

LinePick down, align to the normal.

could you show me an example?..

Take a look at the 'mak/driver' demo in the Blitz3D samples folder.

you can also use aligntovector command using the collisionnx(),ny,nz functions