I don't remember where it starts but the part I was talking about took place in SF airport. It started somewhere in the sky on a straight flat road, then it goes in a spiral down to the ground level (on an airport lane I suppose). I also remember that the angle between the ground and the road in this spiral was very high (about 70-80 degrees) so that if you stop your car you'll fall down to the ground.
I thought Loop is the race with the sanchez in a sphere made of stunting roadblocks. Although I'll check it anyway, cause I don't exactly remember it.
EDIT: Yep, both Loop and WWW are the one I was looking for, many thanks! But as I remember there were some other races made in the same style. Do you remember any other races of that kind?