Total number of motor coaches, buses and trolley buses. Motor coach is passenger road motor vehicle designed to seat 24 or more persons (including the driver) and constructed exclusively for the carriage of seated passengers. Bus is defined as passenger road motor vehicle designed to carry more than 24 persons (including the driver), and with provision to carry seated as well as standing passengers. Trolleybus is passenger road vehicle designed to seat more than nine persons (including the driver), which is connected to electric conductors and which is not rail-borne. This term covers vehicles which may be used either as trolleybuses or as buses, if they have a motor independent of the main electric power supply.