Startup private bus company proposed by Andy Didorosi. He expects to launch in April 2012. The first loop would run between downtown, Corktown, Woodbridge, Midtown, Eastern Market, and Greektown. Fares would be as high as $5.

Detroit has laws on the books against private fixed-route transit / small buses. Henry Gaffney, the head of the DDOT drivers union said he would look into the service. 

Sources:

Detroit Bus Company Aims To Make Up For City's Transit Gaps With Private Enterprise. Huffington Post. 23 February 2012.