ISO 14793:2011 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.