This International Standard specifies test methods for determining the transient response behaviour of heavy commercial vehicles, heavy commercial vehicle combinations, buses and articulated buses, as defined in ISO 3833 for trucks and trailers above 3,5 t and buses above 5 t maximum weight, and in UNECE (United Nations Economic Commission for Europe) and EC vehicle classification, categories M3, N2, N3, O3 and O4. NOTE The open-loop manoeuvres specified in this International Standard are not representative of real driving conditions, but are nevertheless useful for obtaining measures of vehicle transient behaviour — particularly with respect to that which the driver experiences — in response to several specific types of steering input under closely controlled test conditions. For combinations where the response of the last vehicle unit is of importance, see ISO 14791.