Any interested person may file with the Administrator a petition requesting him:

(a) To commence a proceeding respecting the issuance, amendment or revocation of a motor vehicle safety standard, or

(b) To commence a proceeding to decide whether to issue an order concerning the notification and remedy of a failure of a motor vehicle or item of replacement equipment to comply with an applicable motor vehicle safety standard or a defect in such vehicle or equipment that relates to motor vehicle safety.