The California Air Resources Board’s (CARB) Advanced Clean Fleets (ACF) regulations have a number of requirements subject to either a January 1, 2024, deadline (a prohibition on adding new drayage trucks to a California fleet that are not zero-emission vehicles (ZEVs)) or a February 1, 2024, deadline (the reporting requirement for fleets under the ACF-High Priority regulations). Because CARB has sought a waiver from the U.S. Environmental Protection Agency (EPA) to enforce the ACF regulations, CARB will not enforce the deadlines until EPA either grants a waiver or determines a waiver is unnecessary. CARB has reserved the right to require removal from a carrier’s California fleet any truck improperly added to the fleet after the applicable deadline if EPA grants a waiver (or deems a waiver unnecessary). The California Trucking Association has challenged CARB’s authority to promulgate the ACF regulations, so whether the regulations ultimately become enforceable remains unclear.