I totally forgot I asked that question.
Anyway, I was kind of thinking the force field thing with cars and they are metal and therefore, magnetic - well, most of the body anyway. Thought maybe it would help with collisions and stuff.
I knew it would take a very large magnetic field, but I thought if it were something someone seriously considered, then someone with more intelligence than me could figure out a way of making something so big fit into something very small. Kind of like how computers used to be so big, now they are so small.