You'd struggle to tell at a glance, but the car you see here has the most aerodynamically-efficient shape of any car on sale.

The 2014 Mercedes-Benz CLA is the firm's smallest sedan, based on the front-wheel drive A-Class sold in Europe.

Already an efficient shape, the elongated tail of the CLA, a four-door coupe, gives it one of the most streamlined bodies ever seen on the roads, with a drag coefficient of only 0.23--a Prius is rated at 0.25, and the typical car is nearer 0.3.

Streamlined it may be, but the CLA is every inch a Mercedes-Benz.

As you can see in our live photos from Detroit, it features a prominent grille, proudly displaying the famous three-pointed star. The surfacing is a riot of concave and convex metalwork, yet every inch has been designed with air flow in mind.

The A-pillars are designed to cut through the air as cleanly as possible, as are the door mirrors. Special alloy wheel designs minimize air resistance, and Mercedes has paid particular attention to the underbody, with a flat-bottomed muffler and rear diffuser helping air leave the underside of the car as cleanly as it entered.

The interior features a low-slung driving position and a more youthful feel than larger Mercedes-Benz models, with a touch-screen display sitting proud of the dashboard.

Initially, U.S. customers will get the CLA 250. This uses a 2.0-liter, four-cylinder and turbocharged gasoline engine, developing 208 horsepower. Drive goes through a seven-speed dual-clutch automatic transmission, and 4MATIC all-wheel drive will feature in Spring 2014. A diesel model is rumored too--you can find out more in our CLA Detroit Show preview.

What do you think of Mercedes' newest offering? Leave your thoughts in the comments section below.

For more news, images and launch details from Detroit, head over to our Detroit Auto Show page.


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