As Wired magazine reports, the BMC Mini defined the modern econobox 50 years ago: a small front-mounted engine in a front-wheel-drive car that was easy to handle, and compact yet spacious. That set the stage for decades of economy cars going forward, right up to today's cars like the Toyota Corolla. "But now the smallest cars—the Smart Fortwo, Mitsubishi's Japanese-market i, and India's forthcoming Tata Nano—are all shifting gears. Their engines are migrating to the back," Volkswagen Beetle-style.

The report said that the designs aren't exactly the same as the old air-cooled Beetle, however. They're not cantilevered behind the rear wheels, which leads to unpredictable handling. Instead, the new design places the motor under the rear seat and over the rear axle—a kind of rear-mid-engine layout. That allows for more interior room, better safety, and a more balanced chassis than the pendulum-effect you get on wet or icy roads with a pure rear-engine design.

Plus, in very small cars, a front-mounted engine can end up in your lap after a crash, since it doesn't deform to absorb impact, the article said. "Move it to the back, though, and the front crumple zone can be deeper and crush more gradually." And if the car is rear-wheel-drive, the oldest reason in the book still applies—it's cheaper to build, since you're sitting the engine right on top of the wheels you're driving, and less complex, since those wheels aren't also steering.

(Image credit: Feric/Wired)