Interstate Highway System Toll-Free Holiday Act - Prohibits tolls from being collected, and vehicles from being required to stop at a toll booth, for any toll highway, bridge, or tunnel on the Interstate System during any peak holiday travel period.

Directs: (1) the State transportation department or the public authority having jurisdiction over the toll highway, bridge, or tunnel to determine the number and duration of peak holiday travel periods, which shall include, at a minimum, the 24-hour period of each legal public holiday; (2) the Secretary of Transportation to reimburse the State or public authority for the amount of toll revenue not collected by reason of this Act, upon request; and (3) each State or public authority that desires a refund to submit to the Secretary a request for reimbursement, based on actual traffic data, for the amount of toll revenue not collected by reason of this Act during a fiscal year. Specifies that a request for reimbursement shall include a certification by the State or public authority that the amount of the reimbursement will be used only for debt service or for operation and maintenance of the toll facility.