49 CFR 390.25: Extension or Modification of relief from regulations—emergencies.

(a) FMCSA may extend the period of the regulatory relief or modify the scope of emergency relief contained in § 390.23. Interested parties may also request an extension or modification by providing a detailed explanation of the need for an extension or modification of the relief. Any interested party seeking to extend the period of regulatory relief shall send its request to the FMCSA emergency declarations mailbox, FMCSAdeclaration@dot.gov, before the expiration of the period of relief. FMCSA will determine if such relief is necessary by evaluating the circumstances of the ongoing emergency, the need for relief, and the nature of the relief to be provided.

(b) If FMCSA initiates or approves an extension of the regulatory relief, it shall establish a new time limit and may place terms and conditions on motor carriers or drivers relying upon the continued or modified relief. These terms and conditions may include reporting requirements.