It’s an official classification, not ad-speak. Here they are:
TLEV (transitional low-emission vehicle)The least stringent emissions standard in California. California phased-out TLEVs in 2004.
LEV (low-emission vehicle)The minimum standard for all new cars sold in California as of 2004.ULEV (ultra-low-emission vehicle)
SULEV (super-ultra-low-emission vehicle)SULEV emissions are 90% cleaner than the average new model year car.
PZEV (partial-zero-emission vehicle)A PZEV meets SULEV tailpipe emission standards, but has no evaporative emissions (i.e., no unburned fuel leaves the fuel system). A PZEV has a 15-year / 150,000-mile warranty on its emission control components.
AT PZEV (advanced technology partial-zero-emission vehicle)An AT PZEV meets the PZEV requirements, but also meets some of the necessary conditions of a ZEV. AT PZEVs include dedicated compressed natural gas vehicles and hybrid vehicles with engine emissions that meet PZEV standards.
ZEV (zero-emissions vehicle)The emissions of a ZEV are 98% cleaner than the average new model-year vehicle, and has no tailpipe emissions. These include battery electric vehicles and hydrogen vehicles (fuel cell vehicles).