In 1982, we made the first prototype of the Half Toroidal CVT, it was installed in a 1600cc car and a road test was carried out on a US highway. After that prototypes of eight types of the Half Toroidal CVT, from 12hp to 100hp, were developed for automobiles and tested under various conditions. In this paper, the mechanism of the Half Toroidal CVT is discussed and the specifications of all eight types of prototype are detailed. A hydro-electric control system was used in the vehicle test. The signals of the throttle and vehicle speed were input into the computer, and the computer calculated the best ratio of the CVT, and operated a stepping motor. The motor moved the hydraulic 4 way spool valve to change the speed ratio of the CVT, so that we could control the CVT successfully. As a result of these studies, we consider that the Half Toroidal CVT has a potential for automotive transmissions.