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CARB releases proposed Advanced Clean Cars II regulations

10 December 2021

The California Air Resources Board (CARB) has posted draft regulatory language for Advanced Clean Cars II (ACC II) regulations. The main parts of the proposal include Low Emission Vehicle IV (LEV IV) emission standards and an updated Zero Emission Vehicle (ZEV) regulation.

The ACC II regulations—presented by CARB staff at a public workshop held in October—will seek to reduce criteria and greenhouse gas emissions from new light- and medium-duty vehicles beyond the 2025 model year, and increase the number of zero-emission vehicles (ZEVs) for sale.

Building on the May and August 2021 workshops, CARB presented updated analyses and proposals to amend the Low Emission Vehicle Regulation to reduce criteria pollutant emissions and updated analyses and proposals to amend the ZEV Regulation. In addition, updates to the ZEV assurance measures and updates to proposed measures to increase access to ZEVs for priority communities were presented. Statewide costs and emission benefits for the full regulation proposal and two alternatives were also presented.

LEV Regulation Proposal. The ACC II regulations would introduce LEV IV standards for 2026 vehicles that would tighten emission standards for vehicles with combustion engines and address aggressive driving, cold starts and evaporative emissions. Most requirements would be fully phased-in by 2028.

For passenger cars and light trucks, fleet average NMOG+NOx are currently scheduled to reach 0.03 g/mile by 2025 but allow 100% of ZEV sales to count in the calculation. The ACC II proposal is to leave the fleet average at 0.03 g/mile after 2025 but phase-out the inclusion of ZEVs so that by 2028, ZEVs are no longer included in the calculation. It would also phase-out PHEV NMOG+NOx credits for electric driving by 2028 and introduce new certification bins (SULEV15, SULEV25. ULEV40 and ULEV60) in 2026. The LEV160 and ULEV125 bins would only be available through 2025 and 2028 respectively.

Aggressive driving emission standards would be introduced in the way of a new US06 NMOG+NOx standard equal to the FTP standard for the ULEV125 to SULEV30 bins. The US06 standard for SULEV25 to SULEV15 would be fixed at 0.030 g/mile. The option to use composite standards for certification would be eliminated.

The particulate matter standards would be reduced from 6 to 3 mg/mile PM on the US06 cycle with 100% phase-in by 2030. Pure ZEVs are excluded from the requirements as well as the phase-in.

The proposal defines a curve of normalized NMOG+NOx emissions versus soak time which must not be exceeded. For soak times between 10 and 180 minutes, limits lower than the FTP standard are defined by this curve.

To limit cold start emissions, a new quick drive-away NMOG+NOx limit is introduced in the way of an FTP cycle with an 8s idle period at the start of the test. The standard idle period is 20s. The quick drive-away FTP limit is slightly more relaxed than the FTP limit for a 20s idle.

To limit emissions from PHEV vehicles during high power cold-starts, a cold-start US06 test is proposed that would apply to PHEVs unless they are US06 capable.

The evaporative emission standards would be tightened to reduce the running loss standard from 0.05 to 0.01 g/mile. A minimum canister size is also proposed to eliminate "puff" evaporative emissions that are unique to special sealed Non-Integrated Refueling Canister Only System (NIRCOS) gasoline tanks that are common on PHEVs and some HEVs.

For heavier vehicles, many similar changes are also proposed. Class 2b and Class 3 fleet average NMOG+NOx are proposed to be lowered to 0.150 and 0.175 g/mile by 2029 along with the elimination of ZEVs from the fleet average calculation. Four new certification bins are also added to both of these vehicle classes below the current lowest bins. A requirement to meet the FTP NMOG+NOx as well as a CO limit over the US06 cycle is also proposed. To address emissions related to towing, MDVs > 14,000 lbs GCWR would see PEMS MAW in-use test procedures and standards applicable to MY 2026 vehicles with a phase-in of more stringent standards similar to the HD Omnibus in-use program.

ZEV Proposal. The current ZEV sales requirement is proposed to increase to 100% ZEV and PHEVs by 2035. PHEVs would be counted as up to 20% of the ZEV requirement provided they meet SULEV30 or lower emission limits and minimum all-electric driving range including over the US06 cycle. Environmental Justice allowances and pooled ZEV and PHEV from other states could be additionally counted toward the ZEV requirement.

Environmental Justice credits are awarded to manufacturers in MY2026 to MY2031 who take action to help increase affordable access to ZEVs for priority communities by offering a minimum 25% discount based on the vehicle MSRP.

ZEV pooling would allow OEMs to transfer MY2026 to MY2030 credits within a single pool (CA + 177 States) to meet up to 15% of its total obligation in each state in MY 2026. This would decline to 10% of its total obligation in each state in MY 2030 and pooling would end after 2030. OEMs would have to deliver substantial volumes of vehicles in each ZEV state to comply and only credits from excess sales may be transferred to other states.

The ZEV proposal also includes requirements for battery durability, in-use compliance testing and updated battery warranty requirements.

Source: CARB