Can an emergency declaration be extended?

Yes, under 49 CFR § 390.25 FMCSA may extend the 30-day time period of a regional emergency declaration issued under 49 CFR § 390.23(a)(1) taking into account the severity of the ongoing emergency and the nature of the relief services to be provided.  If FMCSA extends an emergency declaration it will establish a new time period and will include any other necessary restrictions.