TMC also began to establish local R&D organizations in response to the full-scale operational start of its overseas production sites, such as Toyota Motor Manufacturing, Kentucky, Inc. (TMMK) in the United States and Toyota Motor Manufacturing Canada Inc. (TMMC). In the United States, TMC established Toyota Technical Center, U.S.A. Inc. (TTC-USA) as an R&D center in California in 1977, where it has since conducted local compatibility evaluation of vehicles for North America. In 1991, TTC-USA moved its headquarter functions to Ann Arbor, Michigan, and built a new testing building there and a prototype plant in Plymouth, Michigan. In 1993, TMC opened in Arizona its largest test track, enhancing its development organization for producing vehicles in North America.