 The DSR formally became the DDOT in 1974 under the Detroit City Charter.Between 2009 and 2012, the system's seven remaining limited and express bus routes (70, 71, 72, 73, 74, 76, and 78) were discontinued.Starting January 1, 2012, management of DDOT was contracted out to Parsons Brinckerhoff, an engineering and management firm.