Section 1956.8, Title 13, California Code of Regulations contains California's emission standards for on-road heavy-duty engines and vehicles, and the following test procedures, as incorporated by reference.
Heavy-Duty Otto-Cycle Engines and Vehicles
"California Exhaust Emission Standards and Test Procedures for 1987 through 2003 Model Heavy-Duty Otto-Cycle Engines and Vehicles" (PDF Download), as amended on December 27, 2000
"California Exhaust Emission Standards and Test Procedures for 2004 and Subsequent Model Heavy-Duty Otto-Cycle Engines and Vehicles" (PDF Download), as amended September 9, 2021
Heavy-Duty Diesel Engines and Vehicles
"California Exhaust Emission Standards and Test Procedures for 1985 through 2003 Model Heavy-Duty Diesel Engines and Vehicles" (PDF Download), as amended on December 12, 2002
"California Exhaust Emission Standards and Test Procedures for 2004 and Subsequent Model Heavy-Duty Diesel Engines and Vehicles" (PDF Download), as amended September 9, 2021
