Volkswagen Chief Executive Martin Winterkorn has resigned, succumbing to pressure following the German automobile company’s admission that it deceived US regulators about how much its diesel cars pollute. "Volkswagen needs a fresh start – also in terms of personnel,” Winterkorn said. "I am clearing the way for this fresh start with my resignation.” The US Justice Department is now conducting a criminal investigation of Volkswagen’s admission to systemically cheating on federal air pollution tests. This scandal has marred the reputation of the world’s largest automaker, sending its shares Monday to the lowest level in more than three years. While Volkswagen are yet to name a successor – saying that proposals on management appointments would be made to a full board meeting on Friday – Porsche chief Matthias Mueller, Audi chief Rupert Stadler and the head of the VW brand, Herbert Diess, are all favourites to Winterkorn.