I've been excited by the possibility of in wheel motors ever since I first heard of them because of the combination of simplicity of the motor, and the massive simplification of mechanical systems of a car. You no longer need all the bits which connect your inefficient internal combustion engine to the wheels, and those bits lose a lot of energy, somewhere around 50% according to what I've read. There is one company that makes buses with wheel motors which quadruple the fuel efficiency of the current best diesel bus, and of course there is the electric mini prototype which got a lot of hype a few years ago.

My biggest problem assessing the technology is my complete ignorance of the mechanical/electrical engineering issues involved. One engineering grad student argued that wheel motors were no good because they destroyed the control of the car by putting all the weight at the very bottom, and that the motors were going to be subject to a lot of shocks in real world use. I don't know enough to evaluate if that is true or not, but I'm hopeful. Anyone here know more?