AT-PZEV

A partial zero emissions vehicle, in the United States, is an automobile that has zero evaporative emissions from its fuel system, has a 15-year (or at least 150,000-mile) warranty on its emission-control components, and meets SULEV tailpipe-emission standards.

In California, PZEVs have their own administrative category for low-emission vehicles. The category was made in a bargain between automakers and the California Air Resources Board (CARB), so that automobile makers could delay making mandated zero-emission vehicles (ZEVs)—electric and fuel-cell vehicles.

The Super Ultra Low Emission Vehicle (SULEV) standard is more stringent than the Ultra Low Emission Vehicle and low-emission vehicle standards. All emissions-related components, including the electric-propulsion parts of hybrid electric vehicles, must be warranted for 15 years or 150,000 miles.

Advanced Technology PZEVs (AT-PZEVs) are at least as "clean" as regular PZEVs and either use no gasoline or have much greater fuel efficiency because they are hybrid electric vehicles.

CARB also prepared a TZEV (Transitional ZEV, formerly Enhanced AT-PZEV) category for plug-in hybrids (PHEVs) and hydrogen vehicles. (Not to be confused with Hydrogen Fuel Cell Electric Vehicles which are certified as ZEV or Zero Emission Vehicles.) In addition to the 15 year or 150,000 mile warranty for zero evaporative (fuel system) emissions, and SULEV tailpipe emissions, PHEVs must also warranty their traction battery for 10 years or 150,000 miles. While PHEVs and hydrogen internal combustion engine vehicles exist, none meet this stringent standard.

...
Wikipedia