It’s a well-known shortcoming of electric cars that they can only be driven short distances. The Chevy Volt, for example, has a maximum range of 50 miles on a single charge. And, while it’s possible to back up the electricity system with a fossil fuel-based one, as the Chevy does, that somewhat takes away from the point of having an electric car in the first place.

It would be much better either if the car could go longer without needing to stop, or if it could somehow be recharged mid-flight, like a long-haul military plane. And, in fact, the second possibility may not be as fanciful as you might think.

Researchers at Toyota Central R&D Labs and Toyohashi University of Technology have come up with what they think is the world’s first mid-drive charging system, based on a similar mechanism that allows trains to travel under overhead wires.

Under the still-experimental system, electrified metal plates are buried under roads, which “up-convert” energy via a radio frequency to a steel belt inside a car’s tires, as well as to a plate sitting above the tire.

Although testing of the system has only involved low voltages so far, the researchers say the system could allow to electric cars to be far lighter than they are today. The electric cars would need smaller battery packs, as they would only need to to get and from the electrified highways.

Anything to reduce the weight of today’s electric car batteries would be a good thing, potentially saving energy and conserving limited lithium supplies. The Chevy Volt’s battery assembly weighs a not-insubstantial 435 pounds, and measures 3.5& cubic feet.