Advanced Clean Fleets Rule Would Require Zero-Emission Truck Purchases in California
If approved, the rule would require California public fleets to purchase 100% zero-emission trucks by the year 2027. Other states are carefully monitoring this rulemaking process and may choose to mirror the regulation.

Photo: Flickr/d-brandsma
The California Air Resources Board (CARB) has proposed and is currently reviewing the new Advanced Clean Fleets rule. If approved, the rule would require California public fleets to purchase 100% zero-emission trucks by the year 2027. Other states are carefully monitoring this rulemaking process and may choose to mirror the regulation as they have done already for other CARB rules and policies.
What is Being Proposed?
The Advanced Clean Fleets rule is the first of its kind in North America. It would transition all purchases of new vehicles with a GVWR of 8,500 lbs. or greater with a phased approach. By 2024, new fleet truck purchases would need to be 50% zero emission. From 2027 onward, 100% of new purchases would need to be zero emission. "Zero emission" includes both electric and hydrogen fuel cell vehicles.
This rule is separate from the Advanced Clean Trucks sales requirement that went into effect in 2020 that was aimed towards manufacturers. That rule required manufacturers to sell set percentages of zero-emission vehicles in the state but had no requirements for buyers. This rule instead applies to fleets.
What is the Timeline?
It is important to note that this rule has not yet been approved. It has been proposed and would be sent to the CARB Board for a decision in December 2021. If approved, the rule would be phased in with an initial 50% purchasing requirement before 100% ZEV purchases are required in 2027.
Proposed Requirement | Deadline |
50% of New Purchases Must Be ZEV* | 2024-2026 |
100% of New Purchases Must Be ZEV** | 2027-onward |
* Fleets in certain low population "designated" counties are exempt from the phase one requirement but would be affected by the 100% 2027 requirement (i.e., Alpine, Amador, Butte, Calaveras, Colusa, Del Norte, Glenn, Humboldt, Inyo, Lake, Lassen, Mariposa, Mendocino, Modoc, Mono, Nevada, Plumas, San Benito; Shasta; Sierra, Siskiyou, Sutter, Tehama, Trinity, Tuolumne, and Yuba Counties).
**Plug-in-hybrids count the same as ZEVs until 2035
What Public Fleet Vehicles Would Be Excluded or Exempt?
Certain public fleets and types of vehicles would be excluded by the rule. Transit vehicles subject to the Innovative Clean Transit regulation are exempt and so are certain types of specialty vehicles. For example, military tactical vehicles, emergency vehicles, motor homes, and school buses are not affected. CARB has also given themselves administrative flexibility to make other case-by-case exemptions.
What Does This Mean for Public Fleets?
This rule has many implications for public fleets, but it would not affect normal replacement schedules. Fleets can continue to operate gas and diesel equipment so long as it is compliant with California Truck and Bus rules, and other compliance requirements. ZEV purchases are only required at the time of normal replacement. However, the deployment of this many zero-emission trucks would require unique planning for fleets.
Generally, zero-emission trucks have more intensive fueling needs than light-duty. Many would require DC Fast Chargers and result in facility electrical and utility transformer upgrades. Load management would need attention at this scale, and the deployment of energy storage may make economic sense.
Medium- and heavy-duty EV infrastructure deployment make take 18 months from start to commissioning. Fleets planning to deploy medium-duty trucks in late 2023 should plan on having their charging station providers selected, begin engaging with their utility, and be ready to begin the permitting plan check process in 2022. Fleet electrification is a team sport and although this rule has not been approved yet, research and internal discussion should begin as early as possible.
About the Author: Michael Terreri is the EV product manager at AssetWorks.
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