Volkswagen (VOWG_p.DE) plans to limit the time staff can remain in certain roles, its supervisory board chairman told a German weekly, in a step to improve oversight at the German carmaker. VW said in September it had cheated U.S. emissions tests and installed software capable of deceiving regulators, wiping billions of euros off its market value and forcing out its long-standing chief executive. The employees concerned will spend only a limited time in certain positions before moving on,” Chairman Hans Dieter Poetsch told Welt am Sonntag in an interview.