Some electric trolleys, subways and trains operate this way, because the vehicle is on a track, and the circuit is completed through a contact overhead. Bumper cars operate similarly, as they are always in contact with a metal floor, which completes the circuit through a pole in the back that touches the ceiling. But road cars can't do this — you'd need something more akin to a third rail system.
That's what Masahiro Hanazawa at Toyota Central R&D Labs in Japan, working with Takashi Ohira at the Toyohashi University of Technology, say they have. Using steel belts in the tires and a metal plate in the road, they can get a similar effect as in slot cars or third-rail powered trains. The energy, running through the plate, is transmitted to the car through the wheels, powering the motor and eliminating the need for batteries.