This International Standard covers high-level safety requirements applicable to automated urban guided transport systems, with driverless or unattended self-propelled trains, operating on an exclusive guideway. This standard only deals with the safety requirements needed to compensate for the absence of a driver or attendant staff who would otherwise be responsible for some or all of train operation functions (see Table 1), depending on the level of automation of the system (see shaded areas in Table 1 and see 3.1 for a definition of the different grades of automation). The requirements of this standard are restricted to transports systems as defined in Clause 5 and to DTO and UTO as defined in 3.1.4 and 3.1.20, respectively (see the shaded areas in Table 1).