Michelin’s shown off a concept car whose “active” wheels contain all the elements you’d expect to find in the car itself: “Why not … use the space within the tire to put as many components as possible, including all the suspension, and make it active, and put in an electric motor, and even eliminate the need for a mechanical transmission?”
Link
(via Futurismic)
(Via BoingBoing.)

Also check out the Dutch Whisper Bus, which uses wheels containing motors.