electric cars without batteries

A fairground attraction for decades -- bumper cars, as they are known in the US because of the rubber bumper around each car, or dodgem cars as they are known in A/NZ.

Those who can remember them in the past will remember the sparks as the overhead pole current collector brushed over energized chicken wire in the ceiling, and the contact shoes on the floor formed a complete, but often broken, circuit.

A newer power supply system uses alternating strips of metal across the floor separated by insulating spacers, and no ceiling grid. The alternating strips carry the supply current, and the cars are large enough so that the vehicle body can always cover at least two strips at any one time. An array of brushes under each car make random contact with whatever strip is below, and the voltage polarity on each contact is sorted out to always provide a correct and complete circuit.

The metal floor is usually an oval track. The controls are usually an accelerator and a steering wheel; the cars can be made to go backwards by turning the steering wheel far enough in either direction, necessary in the frequent pile-ups that occur.