In This June 24, 2015 photo Volkswagen CEO Martin Winterkorn arrives for an official state dinner for Britain's Queen Elizabeth II, in front of Germany's President Joachim Gauck's residence, Bellevue Palace, in Berlin. Winterkorn promised full cooperation with the government following the company's admission it rigged nearly a half million cars to defeat U.S. smog tests. (AP Photo/Markus Schreiber)