Improvements for Heavy-Duty Engine and Vehicle Test Procedures
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Rule Summary
EPA is taking a final action to improve the Greenhouse Gas Emissions Model (GEM) compliance tool for heavy-duty vehicles. This includes amending the procedures for demonstrating compliance with the CO2 emission standards for heavy-duty highway engines and vehicles with several corrections, clarifications, and additional flexibilities. There will be neither significant environmental impacts nor significant economic impacts with this final action.
GEM was used to set standards for the Heavy-duty Phase 2 greenhouse gas program finalized in 2016 and is used today by manufacturers to certify vehicles to these standards.
Additional Resources
- Final Rule: Improvements for Heavy-Duty Engine and Vehicle Test Procedures (pdf) (646 KB, published July 28, 2022)
- Improvements for Heavy-Duty Engine and Vehicle Test Procedures (Response to Comments) (pdf) (July 2022, EPA-420-R-22-014)