Smart mhd's stop-start technology saves petrol

Smart has unveiled a new version of its iconic supermini that reduces the cost of car ownership and its harm to the planet. The Smart mhd, which we tested in this video, looks much like any 2009-model Smart Car. It uses Smart's new micro hybrid-drive technology, however, to improve fuel economy. This switches the engine off as soon as you fall below a speed of 5mph under braking, and turns it back on again when you press the accelerator pedal.