Seats must be secure and fixed. They must not have sharp edges or protruding objects likely to cause injury during speed changes or collision. Temporary removal of seats is permitted but all seats must be present during regular inspection. Additions of seats is not permitted unless such amendment is approved by the inspection stations. Changes to the registered seating arrangement of buses, whether to add, remove or change, must be approved by both the Icelandic Transport Authority (submit drawings) and the inspection station (after approval of the drawing).