Zothecula writes "While quick charging technology installed at strategic points along a planned route might be a good fit for inner city buses, it's not going to be of much use to electric vehicles that stop infrequently. Volvo sees our future long-haul trucks and buses drawing the juice they need from the road itself, making large onboard batteries a thing of the past. 'The two power rails/lines run along the road's entire length. One is a positive pole, and the other is used to return the current. The lines are sectioned so that live current is only delivered to a collector mounted at the rear of, or under, the truck if an appropriate signal is detected. As an additional safety measure, the current flows only when the vehicle is moving at speeds greater than 60 km/h (37 mph). "The vehicle is equipped with a radio emitter, which the road segments can sense," explains Volvo's Per-Martin Johnansson. "If an electric vehicle passes a road segment with a proper encrypted signal, then the road will energize the segments that sense the vehicle.'"