First, you need to make sure that your collisions are being detected. Sounds like they collide pretty well, I’m assuming that the vehicle stops when it hits the character?
If it stops, then you’re on to something. Now all you have to do is turn on the physics of the character and tell it what to do when it gets hit by a moving vehicle.
You can make a steep ramp incline and hover a sphere over it, but until you tell that sphere that it can actually move and how to move, it’s just going to stay right where you put it.