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Heavy Trucks, Buses, and Engines

Heavy Trucks, Buses, and Engines

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This page presents emission-related information about heavy-duty highway engines, such as those used in trucks and buses. Much of this content is focused on diesel engines, but requirements also apply for gasoline-fueled and other spark-ignition engines. The requirements apply to engines installed in all vehicles with Gross Vehicle Weight Rating above 14,000 pounds, and to some engines installed in vehicles with Gross Vehicle Weight Rating between 8,500 and 14,000 pounds. This page describes the emission standards and related requirements for criteria pollutants -- NOx, HC, CO, and PM. See Greenhouse Gas Standards for requirements that apply for CO2, N2O, and CH4.

General Information

Regulations and Related Documents

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Certification Guidance

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