The Commissioner of Social Security shall pay travel expenses, either on an actual cost or commuted basis, to individuals for travel incident to medical examinations requested by the Commissioner of Social Security in connection with disability determinations under this subchapter, and to parties, their representatives, and all reasonably necessary witnesses for travel within the United States (as defined in section
1382c
(e) of this title) to attend reconsideration interviews and proceedings before administrative law judges with respect to any determination under this subchapter. The amount available under the preceding sentence for payment for air travel by any person shall not exceed the coach fare for air travel between the points involved unless the use of first-class accommodations is required (as determined under regulations of the Commissioner of Social Security) because of such person’s health condition or the unavailability of alternative accommodations; and the amount available for payment for other travel by any person shall not exceed the cost of travel (between the points involved) by the most economical and expeditious means of transportation appropriate to such person’s health condition, as specified in such regulations. The amount available for payment under this subsection for travel by a representative to attend an administrative proceeding before an administrative law judge or other adjudicator shall not exceed the maximum amount allowable under this subsection for such travel originating within the geographic area of the office having jurisdiction over such proceeding.