Investigations on the feasibility of ETC for motorcycles were conduct- ed for seven years, including tests to verify the safety and operation of communication devices using data of trials in which about 5,500 monitor motorcycles participated, involving over 280,000 trips. In November 2006, full-scale deployment started on all expressways, and in just half a year, on-board units were installed in 30,000 motorcycles, and the num- ber is expected to increase sharply.