Historical
BS ISO 16121-4:2005
Road vehicles. Ergonomic requirements for the driver's workplace in line-service buses. Cabin environment (British Standard)
ISO 16121-4:2005 applies to the driver's workplace in low-floor line-service buses designed for the carriage of passengers, comprising more than eight seats in addition to the driver's seat, and having a maximum weight exceeding five metric tonnes and an overall width exceeding 2,30 m.
It gives the minimum requirements for the cabin environment.
British Standards Institution [bsi]