CARB Advanced Clean Fleets Rule Takes Effect, Mandating Zero-Emission Truck Purchases

CARB Advanced Clean Fleets Enforcement Begins

The California Air Resources Board (CARB) has begun enforcement of the Advanced Clean Fleets (ACF) regulation, the most aggressive zero-emission vehicle mandate for commercial trucks in the world. The regulation requires large fleets operating in California to begin transitioning to zero-emission vehicles (ZEVs).

Compliance Requirements

Under the ACF rule, fleets operating 50 or more trucks in California must ensure that a minimum percentage of new truck purchases are ZEVs. For 2026, the requirement is 10% for drayage fleets and 5% for other large fleets. The percentages increase annually, reaching 30% by 2028 and 50% by 2030 for most fleet categories.

Infrastructure Challenges

Fleet operators report that charging and refueling infrastructure remains the primary barrier to compliance. Installing DC fast charging at fleet terminals requires significant electrical infrastructure upgrades, with costs ranging from $500,000 to $2 million per facility depending on the number of chargers and required utility service upgrades. Lead times for utility interconnection can exceed 18 months.

Exemptions and Flexibility

CARB has built several flexibility mechanisms into the rule. Fleets that can demonstrate ZEV unavailability for specific applications or that face infrastructure delays can apply for exemptions. A credit banking system allows fleets to earn credits for early ZEV purchases that can be used in later compliance years.