Why can't my car jump off of ramps in a realistic fashion?

I'm working on a simple racing game, and I love the way my car handles while driving on flat surfaces. The problem is that whenever it hits a bump in the road or reaches the end of a hill, the car gets tossed into the sky. It's a bit hard to explain, but it seems like the physics engine thinks the car is driving at a higher speed than it is, so that when it gets airborne it flies way too far. Anyone got any idea how to fix this? I want the car to be able to jump off of ramps in a realistic fashion, but at the moment this just doesn't work...

If the car has the right speed and angle when leaving the ramp, but flies way too far when it is airborne, maybe the gravity is set too low? Generally, gravity is the only setting affecting how fast objects fall to the ground, unless you have some really extreme air resistance settings, or other forces are affecting the car.

Started with the same setup from Andrew Gotow's blog and run into similar problems.

After reading Flashbang Studios’ Unite article I switched to a setup with Raycast Colliders and now it works.

http://unity3d.com/support/resources/unite-presentations/physics-the-right-way