Q: What Are California's Emissions Standards?

The emissions standards for California are quite extensive. The state standards are more stringent than the federal standards and they cover a wide range of vehicle emission types. A growing number of other states, and foreign countries, are adopting California’s emissions standards for their areas.

In general, California emissions standards are divided into three levels: LEV (Low Emission Vehicle)/Tier 1, LEV II/Tier 2, and LEV III/Tier 3.

LEV standards are applied to vehicles through model year 2003. LEV II standards apply to model years 2004 - 2010. LEV III standards apply to model years 2015 - 2025.

Tier 1 vehicles are divided into three separate groups:

• Passenger cars
• Light duty trucks below 6000 GVWR
• Light duty trucks above 6000 GVWR

Tier 2 encompasses all Tier 1 vehicles and includes light duty trucks above 8500 GVWR

Tier 3 replaces Tier 2

Within the LEV set of standards, there are further classifications of emissions by vehicle type. These include:

• Transitional Low Emission Vehicles (TLEV)
• Low Emission Vehicles (LEV)
• Ultra Low Emission Vehicles (ULEV)
• Super Ultra Low Emission Vehicles (SULEV)
• Zero Emission Vehicles (ZEV)

California emissions standards cover much more, like heavy duty engines, off-road diesels, marine engines, and locomotives. What I’ve covered here is just a thumbnail sketch of the current legislation.