(9)Proof of fulfilment of compliance with minimum standards of physical and mental fitness for driving by drivers of vehicles used for the transport of persons or goods should be provided when the driving licence is issued and periodically thereafter. Such regular control in accordance with national rules of compliance with minimum standards will contribute to the free movement of persons, avoid distortions of competition and better take into account the specific responsibility of drivers of such vehicles. Member States should be allowed to impose medical examinations as a guarantee of compliance with the minimum standards of physical and mental fitness for driving other motor vehicles. For reasons of transparency, such examinations should coincide with a renewal of driving licences and therefore be determined by the period of validity of the licence.