Sun Tran is the public transit system serving the city of Tucson, Arizona. In 2021, the system had 13,533,100 rides, or about 48,700 per weekday as of the second quarter of 2022. 100% of the fleet utilizes clean-burning fuels, such as compressed natural gas (CNG), biodiesel, and hybrid technologies. In addition to more than 40 bus routes, the system also includes the Sun Link modern streetcar line.