Consultant report

Benefits of adopting California’s Advanced Clean Cars II standards in sixteen U.S. states

This report documents the technical steps and findings of an evaluation of the benefits of adopting California’s Advanced Clean Cars II (ACC II) standards in additional states. The states analyzed are: Colorado, Connecticut, Delaware, Maine, Maryland, Massachusetts, Minnesota, New Jersey, New Mexico, Nevada, New York, Oregon, Rhode Island, Vermont, Virginia, and Washington.

The emission reductions achieved from the adoption of the California ACC II program vary by calendar year, program start date (model year 2026 or model year 2027), and state. By calendar year 2040, the LDV emissions reductions ranged from 40% to 54% for NOx, 16%-22% for PM2.5, and 57%-76% for CO2e. Well-to-wheel emissions reductions ranged from 9% to 120% for NOx, 2%-57% for PM2.5, and 54%-100% for CO2e. Delaying program implementation by one model year leads to a net loss of benefit of 7.5% in calendar year 2027, declining to 3% in calendar year 2040. All states showed a net health benefit in the modeling.