Daniel Ammann, president of GM, speaks during the Wall Street Journal D.Live global technology conference in Laguna Beach, Calif., on Tuesday. “The approach that we are taking to that is to control a lot of that system ourselves because it allows us to move more quickly,” Mr. Ammann said at The Wall Street Journal’s WSJD.Live technology conference here. At first, GM seemed eager to team up. In early 2016, for example, GM announced a $500 million investment in Lyft Inc., where Mr. Ammann sits on the board of directors, and a partnership with the ride-sharing company to develop self-driving vehicles. But now the two companies appear more interested in going it alone. In July, Lyft said it was creating its own autonomous-car development division , and in August, GM said it had begun testing its own ride-hailing app for self-driving cars. Initial tests of the app are only for […]