General Motors’ latest video is pretty unconvincing. While it has alternative-fuel cars at the Detroit Auto Show on this week, the ones that are ready for sale are, for want of a better term, gas guzzlers. And they need to be promoted. The Chevrolet Corvette ZR-1 and Cadillac CTS-V look the business, and GM says that it’s trying to make high horsepower ‘a little more responsible’.
   How? The Corvette ZR-1 ‘is built entirely of lightweight material, aluminum, magnesium, and carbon fiber. It has one of the best fuel economies in its class,’ says the company. Bear in mind that it considers other cars in its class some of the more exclusive supercars out of Europe and none of them will likely see any figure over 20 mpg.
   It only tells us that the Caddy has 550 bhp and 550 lb ft of torque, which doesn’t sound that green to us.
   Still, it’s consumer demand that GM is really trying to tap in to, and consumer behaviour just hasn’t changed sufficiently given where the planet is.