(a)(1) Any person, sole proprietorship, partnership, corporation, or other entity served with a subpoena issued under § 510.4 may file with the Deputy Administrator a motion to modify, limit, or quash that subpoena. If there is no Deputy Administrator, or the Deputy Administrator is not available, such motions shall be filed with and decided by the Associate Administrator for Administration. A motion to modify, limit, or quash must be filed not later than 15 days after the service of the process or five days before the return date specified in the process, whichever is earlier, except that, if the process is served within five days of its return date, such motion may be filed at any time before the return date. Any motion must set forth the grounds and theories of why and how the party believes the process should be modified, limited, or quashed and must contain all facts and arguments which support those grounds and theories.

(2) The Deputy Administrator may, upon receiving a motion filed pursuant to paragraph (a)(1) of this section:

(i) Deny the motion;

(ii) Modify the return date of the subpoena;

(iii) Modify, limit or quash the subpoena;

(iv) Condition granting the motion upon certain requirements; or

(v) Take any other action he or she believes to be appropriate in the circumstances.

(3) The Office of the Deputy Administrator serves the decision on the motion on the moving party or the counsel or representative of the moving party. This service may be made by personal service, by registered or certified mail, or by reading a copy of the decision to the moving party or the counsel or representative of the moving party.

(4) A denial of any motion properly filed under this section shall be in writing, and shall contain a brief statement of the facts involved and the conclusions drawn from those facts by the Deputy Administrator.

(b) The Deputy Administrator's decision on the motion to modify, limit, or quash, filed under paragraph (a) of this section is not subject to reconsideration by NHTSA.