Mercedes-Benz has unveiled a design concept at the Detroit motor show called the Vision GST.

The GST, or "Grand Sports Tourer" describes an original, new vehicle category which brings together features from established car concepts.

The maker says it is a saloon, estate, MPV and sport utility vehicle (SUV) in one -- but, above all a car delivering long-distance driving pleasure.

At roof level, a large area of special electrochromic glass extends from the front windscreen to the rear, and the occupants can alter the tint at the touch of a button according to the intensity of the sun.

Equally striking are the side windows of the design study: omitting the B-pillar has created a large area of glass, reinforcing the sporty appearance of the vehicle.

Butterfly doors are a further highlight of the Vision GST. They open in opposite directions, each at an angle of 90 degrees, offering unique ease of access and opening up new design possibilities for the interior.

Hand-crafted materials such as wood, leather and aluminium underline the exclusive feel of the interior of the Vision GST. There are comfortable, electrically adjustable individual seats for the driver, front passenger and the rear passengers, with an integral belt system.

A third row of seats for two further passengers is also available in the rear, which means that the Vision GST can comfortably seat a total of six.

Beneath the bonnet of the Vision GST is a 360 horsepower, 5.5-litre V8 engine from Mercedes-AMG.