The gravity car concept solves my biggest complaint about today's slot cars - they are just too unrealistically fast and "glued to the track." Decades ago, when slot cars were invented, they traveled at a more-or-less realistic speed, whereas today's slot cars are traveling at a scale 1,000 mph or so. With the car now held on the track by magnets, the driver hardly ever has to take his thumb off the controller switch. This gravity car idea yields much more realistic action (even though the camera speed has to be cut in half to get there).