Green is new black in Detroit

Green themes have dominated this week's North American International Auto Show in Detroit, with each company flaunting their green credentials.

But green doesn't necessarily have to be lean - as some leading manufacturers have sought to reduce the carbon output of their vehicles without sacrificing their performance.

Among the high-performance coupe action on the show floor was Fisker Automotive's Karma plug-in hybrid sports car.

The vehicle is a challenge to the vision of hybrids as dull-but-worthy commuter boxes - protecting the environment at the expense of luxury.

The Karma is capable of 0-60mph in just 5.8 seconds and has a top speed of 125mph.

Yet the company's chief executive, Henrik Fisker, claims the car is greener than a Toyota Prius, saying.

Fisker - who designed both the BMW Z8 and Aston Martin DB9 - said the car was "an environmentally friendly car without compromise" and that it would make 'green' seem sexy.

The Lexus LF-A Roadster has also been attracting attention.

A soft-top version of the coupe shown 12 months ago, the car is capable of generating 500bhp from a front-mounted five-litre V10 - although is it not quite as clean as the Fisker.

A less expensive, but no less important coupe on display at the show is the Cadillac CTS Coupe.

The vehicle was a surprise unveiling at the show, with Cadillac hoping its two-door angular-style and 3.6-litre V6-engined might just be the car to kick-start flagging UK sales.