GM’s three Chevy city cars drew a great deal of attention at the New York show; all three are genuine, Fiat Panda-sized sub-B segment prospects. However, Autocar has learned that the chances of a Chevrolet model that small going on sale in the US are very slim, according to company product development boss Bob Lutz.The Beat, Groove and Trax concepts are based on GM’s upcoming global mini car platform, which will come with three-cylinder petrol and diesel engines as the main powerplants of choice.The Beat is designed as a sporty, highly-specced, urban car, which gets a 1.2-litre engine and auto 'box, the Groove is a ‘tougher’ baby utility car with a 1.0-litre diesel engine, and the Trax a ‘crossover’ city car. Lutz told Autocar that a car similar to these concepts could appear on the US market in the future, but they would have to be "one size bigger to meet the very severe American crash-test requirements". He also claimed that petrol would have to climb to "$4 a gallon" before significant numbers of American car buyers would downsize into a supermini.In reality, GM’s cars based on this platform will be entering what’s expected to become a massive new global market for inexpensive entry-level cars, to be sold mainly in developing countries but also in Western Europe. Many will be wearing the Chevy badge, a brand that is currently shifting 4.5 million units each year and is experiencing "double digit" sales growth in some markets, according to Lutz.However, with Chrysler already committed to entering the supermini segment in the states through a deal with Chinese car-maker Chery, GM could follow suit by developing a slightly larger version of one of the New York trio for the road; it could even be the next Vauxhall Corsa.