that one can be a "master" (with a driver) and the following vehicle(s) are "slave" (controlled by the driver in the "master" vehicle) as a sort of "road train" in order to increase passenger or payload capacity. a positioning system for determining the current location of the RPEV; and a scheduling and dispatch computer so that many RPEV's can be accommodated efficiently on any particular length of road with embedded transmission coils. Such a system could be adapted for use with remote drivers or automatic control over closed roadway circuits such as warehouses and theme parks. Online Electric Vehicles (OHVs) use pick-up equipment underneath the vehicle then collects power through non-contact magnetic induction, which may imply a similar electrical design. Wired energy transfer Trolleybuses use overhead cables which could also be used for cars, as shown in a photograph (right) carried by an encyclopedic magazine about 1910. Overhead power lines The twin overhead power lines are usually copper conductors with a flat surface, which are supported by a steel catenary wire. A pole or pantograph extends from the vehicle and presses 'slippers' or 'skates' against the conductors to complete the circuit. These slipper or skate contacts are frequently coated with graphite, or have a carbon block to reduce friction and ensure a good (low resistance) electrical connection. Since buses are scheduled, traffic conflicts are rare. If the overhead dual power line infrastructure was used randomly by private users, then some sort of management system would be required. The simplest would be to provide the vehicles some limited autonomy so that they could simply disconnect when arriving at each intersection and reconnect when they joined the next section. A more sophisticated traffic management system, as proposed by USA Patent 6421600 (above) could facilitate transit where there are many vehicles wishing to draw power from a particular section of the infrastructure. Recent improvements in trolleybus design include the automatic connection and disconnection of power poles either by the driver or in the event of mechanical dis-engagement from the overhead wires, so that the driver can remain in control, using on-board battery power. Better materials and motion dynamics modeling allow speeds up to about 80 km/h so that trolleybus behavior is flexible and totally comparable with regular autonomous vehicle performance, even at crossings and road-junctions Ground-level power supply Ground-level power supply is an alternative to overhead power lines. The most common version is