21.1. Despite section 21, a four-wheel all-terrain vehicle on which the manufacturer has not installed a passenger seat may be modified to add one provided it is installed according to the instructions and recommendations of the seat manufacturer.
An operator of a vehicle modified in accordance with the first paragraph must hold a certificate obtained from an officer authorized by the Government attesting that the operator has the competence and knowledge required to operate such a vehicle when transporting a passenger, unless the operator is otherwise authorized to do so under the legislation in force in the operator’s place of residence.