"The ultimate responsibility, for where we've gotten and how we've gotten here rests on my shoulders," Kalanick wrote in an email to employees. "There is of course much to be proud of but there is much to improve. For Uber 2.0 to succeed there is nothing more important than dedicating my time to building out the leadership team. But if we are going to work on Uber 2.0, I also need to work on Travis 2.0 to become the leader that this company needs and that you deserve."