Buses are vehicles with more than 9 seats, including the driver’s, which, because of their construction and fittings, are mainly intended for the transport of people and luggage. As a curiosity, comment that included in this category the trolleybus, which does not circulate by rails, but is connected to an electrical line.
Within this category (M) we can differentiate those whose maximum mass does not exceed 5 tons (M2), and those with maximum mass greater than 5 tons (M3). Both will be able to provide space for passengers on foot.