I spotted the ramp in Jose's picture and asked what ruling he had made regarding jumps.
I made up that you need to move at least 3 hexes in a straight line in order to make the jump. Otherwise you don't get enough momentum, fall to the next hex and take damage as crashing. If you make it, the car flies over half the hexes you moved without turning before (round down). That way, if you move 4 hexes in a straight line (included the one the ramp is in), you fly two hexes from it (no risk of crashes with other cars, of course) and land on the third. So the idea is that it can improve your movement if you can pull it.
It makes sense.