Understanding California’s Advanced Clean Cars II Regulation

The Advanced Clean Cars II (ACC II) regulation aims to reduce light-duty vehicle emissions in California by 50% by 2040, mandating that 100% of new vehicle sales be zero-emission vehicles (ZEVs) or plug-in hybrid electric vehicles (PHEVs) by 2035. The regulation applies to original equipment manufacturers (OEMs) selling more than 4,500 light- and medium-duty vehicles annually, utilizing a 'vehicle value' accounting system to track compliance. OEMs can accrue value through ZEV and PHEV sales, environmental justice credits, and flexibility measures such as trading, banking, and pooling values.

• The ACC II regulation mandates that by 2035, 100 percent of new vehicle sales must be either zero-emission vehicles (ZEVs), which include battery-electric vehicles (BEVs) and fuel-cell-electric vehicles (FCEVs), or plug-in hybrid electric vehicles (PHEVs).
• Compliance is required for original equipment manufacturers (OEMs) selling over 4,500 light- and medium-duty vehicles per year; those selling fewer than 4,500 are exempt until the 2035 mandate.
• ACC II replaces the credit-based system of the original ACC rule with a 'vehicle value' accounting system where ZEVs equal one value and PHEVs earn a partial value (0.63 to 1) based on range. PHEV values are capped at 20 percent of annual requirements.
• OEMs can earn environmental justice (EJ) credits—capped at 5 percent of annual requirements—by providing minimum warranty and durability, facilitating charging, or participating in community mobility programs with reduced-priced ZEVs.
• The regulation is projected to reduce light-duty vehicle emissions in California by 50 percent by 2040, which the American Lung Association suggests could help avoid 110,000 premature deaths and 2.78 million asthma attacks between 2020 and 2050.

APA

RMI (2023). Understanding California’s Advanced Clean Cars II Regulation. https://rmi.org/resources/understanding-californias-advanced-clean-cars-ii-regulation/

Chicago

RMI. Understanding California’s Advanced Clean Cars II Regulation. 2023. https://rmi.org/resources/understanding-californias-advanced-clean-cars-ii-regulation/.

Wikipedia

{{cite report |author=RMI |title=Understanding California’s Advanced Clean Cars II Regulation |date=13 June 2023 |url=https://rmi.org/resources/understanding-californias-advanced-clean-cars-ii-regulation/ |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{rmi2023understanding, author = {{RMI}}, title = {{Understanding California’s Advanced Clean Cars II Regulation}}, institution = {RMI}, year = {2023}, month = jun, url = {https://rmi.org/resources/understanding-californias-advanced-clean-cars-ii-regulation/}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }