ISO 16121-2:2011 specifies the requirements for the driver's field of view to the area in front of the vehicle, to the entrance opposite the driver's seat and the interior compartment.

ISO 16121-2:2011 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.