The buzz in the air at the start of the US’s biggest motor show was of an electric nature. The growing interest in hypbrid and even so-called “plug-in” electric cars was one of the main themes at the calendar event for the world auto industry. Manufacturers are increasingly turning to alternative power systems for their vehicles. But BMW chief in America, Tom Purves, said the traditional market is still booming: “It was a record year, actually it was a record year after record year recently, and that is great for BMW, and I think it shows just how much interest there is in the premium car business here in the United States. We were 3 percent ahead of the market and that was great for us.”Ailing General Motors swept the awards, winning top honours in the best car and best truck categories. The winners at the Detroit show were chosen by a jury of 49 auto writers in the United States and Canada. The recognition represents the latest sign of a turnaround at GM, which just a year ago faced daunting threats of bankruptcy.