California’s Air Resources Board has amended the Transportation Refrigeration Unit Regulation for carriers that acted in advance of the deadline for compliance.

The reefer rule mandates upgrades or replacement of reefer engines to meet low-emission TRU standards by Dec. 31 of the seventh year after the model year of the reefer unit.

Under CARB’s amendment, owners of model year 2003 and older reefer engines that met low-emission reefer standards by Dec. 31, 2008, won’t have to meet ultra-low reefer standards until Dec. 31, 2016, a year later than previously required.

CARB fines for TRU violations range from up to $500 for each occurrence up to $1,000.