On Thursday, a new autonomous trolley hit the streets of Knoxville, Tennessee. The 12-seat vehicle provided by Olli is being integrated in the city’s public transit system. It is the third such self-driving project to land in the United States this year. In January, Las Vegas debuted a driverless bus to ferry passengers along a three-block route. A couple months later, California began testing a squat self-driving bus in parking lots. Then at SXSW, local transit authority Capital Metro demonstrated its self-steering coach among festival goers. While major companies like Uber, Tesla, and Apple promise to be the big sellers of autonomous car brains and bodies, it seems the earliest companies to actually put their wheels on roads will be the unknown players powering public transit.