The almost 4 miles Sun Link modern streetcar started operations in Tucson on July 25, 2014. Ride it for free on July 23, from Mercado San Agustin to the University of Arizona, with stops downtown, the 4th Avenue shopping district, Main Gate Square. It’s also a very cool (air conditioned) ride.
Updates on their FB page:https://www.facebook.com/TucsonStreetcar/?fref=ts