Technical standards

Innovative Clean Transit

The Innovative Clean Transit (ICT) regulation sets zero-emission (ZE) bus fleet purchasing requirements for California transit agencies. This rule does not apply to the following transit agencies: school districts, Amtrak, Caltrain, and Caltrans. It also does not apply to the following vehicles: school buses, trolleybuses, and vehicles on rails.

Separate requirements exist for large and small transit agencies. A large transit agency is defined as a transit agency that operates in either the South Coast or San Joaquin Valley Air Basin and operates > 65 buses annually or a transit agency that operates outside of the South Coast and San Joaquin Valley Air Basins and operates ≥ 100 buses in areas with a population ≥ 200,000 people.

The ICT regulation requires that the number of ZE buses that need to be purchased every year by an agency needs to be equal to at least the number of new bus purchases multiplied by the percent requirement, rounded to the nearest whole number. To encourage early acquisition of ZE buses, Bonus Credits are awarded for ZE buses already in the fleet or placed into service before 2022. One Bonus Credit can replace one ZE bus purchase. The minimum required number of ZE buses can be met with any combination of new ZE bus purchases and Bonus Credits. Bonus Credits can only count once towards meeting the ICT requirements. Because Bonus Credits expire in 2028, from 2029, all new buses purchased by transit agencies must be ZEVs.

In addition to credits, CARB will allow transit agencies to implement and operate a ZE Mobility Program instead of purchasing a ZE bus. A ZE Mobility Program is a program that provides other ZE mobility services (bikes, scooters, other ZEVs with GVWR ≤ 14,000 lbs., or a combination of these). A large transit agency’s program must achieve 320,000 passenger miles per year, and a small transit agency’s program must achieve 180,000 passenger miles per year in order to replace one ZE bus purchase.

Advanced Clean Trucks

The Advanced Clean Trucks (ACT) rule establishes ZE sales requirements for all manufacturers that certify on-road vehicles with GVWR > 8,500 pounds for sale in California. This regulation does not apply to school districts with school bus-only fleets, transit agencies subject to the ICT rule, or emergency vehicles. Additionally, manufacturers selling 500 or fewer heavy-duty trucks (HDT) in California are exempt but can generate credits to be banked, traded, or sold (see below).
Starting with model year (MY) 2024, truck manufacturers must meet the following ZEV sales requirements:

Compliance with the ACT regulation is based on a credit and deficit accounting system. Deficits are accrued based on a manufacturers’ total HDT sales each year; this includes sales of internal combustion, ZEV, and ‘near zero-emission vehicles’ (NZEV), which are defined as hybrid electric vehicles with externally rechargeable energy storage systems that allow for an all-electric range (i.e., PHEVs). Both credits and deficits are calculated. Deficits are calculated per sales group by multiplying the number of vehicles sold by the percent sales requirement and a weight class multiplier (WCM). Credits are calculated per sales group by multiplying the sales of ZEV by the appropriate WCM. The WCM serves to account for larger trucks emitting more; manufacturers with larger trucks that emit more will accrue more deficits that need to be offset with more ZEV and NZEV credits. NZEV multipliers are calculated by multiplying the respective ZEV credit value by 0.01 and the all-electric range of the NZEV in miles; this multiplier is capped at 0.75 and will always be 0.75 starting in 2030 when eligible NZEVs must have a minimum all-electric range of 75 miles.

To reward early sales of ZEVs, credits can be accrued with ZEV and NZEV sales starting with MY 2021. These early credits can be banked until MY 2030. Once the MY 2024 sales requirements begin, excess credits can be banked for five subsequent model years. Each model year, manufacturers must generate or yield banked credits equal to the number of deficits, with NZEV credits meeting up to at most half of deficits. Additionally, although any credits generated can be used to cover any deficits generated by Class 2b–3 and Class 4–8 vehicles, deficits generated by Class 7–8 tractors can only be met with credits generated by Class 7–8 tractors. However, manufacturers that accrue 25 or fewer deficits from Class 7–8 tractors can offset these deficits with credits from any group. Manufacturers have one model year to make up outstanding deficits, which can only be covered with ZEV credits. Credits can also be traded and sold between manufacturers.

Aside from manufacturer sales requirements, the ACT includes a requirement for large entities, large fleet owners and brokers, and government agencies that operated HDVs in 2019 to report business practices and emissions reductions goals. CARB will use this information to develop future ZEV purchasing requirements.

The following states have also adopted ACT – Massachusetts, New Jersey, New York, Oregon, and Washington.

Advanced Clean Fleets

As of August 2021, CARB is developing the Advanced Clean Fleets rule, and a final staff proposal and Board consideration are expected by the end of 2021. Preliminary materials on the forthcoming rule have been released by CARB staff. According to these materials, the rulemaking will attempt to achieve ZE truck and bus fleet operations in California by 2045 (and earlier where possible) and will include fleet purchasing and operating rules for both public and private fleets. It is expected to prioritize benefits in disadvantaged communities and apply to vehicles with a GVWR > 8,500 pounds—excluding transit vehicles covered by ICT, school buses, and emergency vehicles.

Zero-Emission Airport Shuttle

The Zero-Emission Airport Shuttle regulation requires ZEV purchases for shuttles that operate at or near regulated airports in California. The rule applies to fleet owners of Class 2b–8 commercial vehicles with GVWR > 8,500 pounds that transport passengers to and from regulated airports. There is a purchasing requirement starting in 2023, when all new shuttle purchases must be ZEVs. The ZE fleet composition requirement compliance schedule is shown in the table below:

This regulation does not apply to vehicles subject to the ICT regulation.