Patent applications acquired by GM Inside News suggest that General Motors is looking at ways of altering the shapes of its cars once they're on the road. By changing a car's roofline or even its width, GM appears to be working on ways to make cars more or less aerodynamic on the fly.

GM's application for a "Method and Systems for Reconfiguring a Vehicle Geometry," show vehicles with body panels that can move to accommodate more or fewer passengers.

While GM has allowed for a car that transform itself from a coupe to a wagon depending on how many people it must carry, the roof could also descend completely into the car if there are no passengers at all, which would have particular benefits for autonomous vehicles.

If an autonomous car were sent out to pick you up at, say, the airport, it might be completely empty on the way there. There's no need, then, to have any passenger area at all. And since winshields and are an aerodynamic drag, simply folding the roof flat would improve the car's coefficient of drag enormously, wasting less fuel on the way to picking you up.

The actual disappearance of the roof could happen in a number of ways, but GM provides the example of a roof that splits apart in the middle, with each side slipping into the body, like your current car's windows.

And to cover the interior-or what's left of it-a kind of soft-top could unfurl. In so doing, the car would effectively have a tonneau cover to keep the elements (wind, rain, etc) out of the car.

The advantages could extend beyond just aerodynamics, though. Contained within the patent is the ability to change body panels along the side of the car. By changing these, your car could effectively suck in its gut. That, along with making it slip through the air more easily, could also help you park in a narrower space.

Here, GM specifically evokes the idea of charging an electric vehicle, too, meaning that GM could, hypothetically, build charging banks for its cars with more chargers and fit more of its slimming cars in a given area.

While the idea isn't limited to autonomous vehicles, it does seem that the weight of the system (all the motors that help to retract the roof, the extra load-bearing stiffening, etc.) would require the aerodynamic gains to be fairly substantial to justify its application. With that in mind, the system would likely work best on autonomous cars.

Although the patent could be applied to private vehicles (to, say, increase or decrease headroom), many of its advantages might best be utilized by an autonomous taxi service. Aerodynamic when empty, such a vehicle could also turn itself into a little bus when the seating was required.

Equally, in taxi mode, it could maintain some aerodynamic advantages by requiring its passengers to sit in the middle and by folding down either end of the car (as in the first illustration, above).

By folding itself into a number of shapes, one vehicle could do the work of many. And without the need for a driver to get out, the vehicles could suck in their guts and make more of a parking lot when they weren't in use.

additional reporting by Dennis Chung

Lead image by Ivan Bandura - Bumblebee, CC BY 2.0, Link