Reminds me of a Subaru Forester I owned. It had a badge 'pzev' which apparently meant 'partial zero-emissions vehicle'. Which meant what? not zero emissions certainly. It was a regular gas car.
Rather, it's a term for a silly thing California allows automakers to do to get around the requirement of selling actual zero-emissions vehicles: https://en.wikipedia.org/wiki/Partial_zero-emissions_vehicle
In California and like places, does it get you into the car pool / hybrid/ electric / bus lane? Is that part of why they colored it green -- so it looks like / is apparent that you qualify?
P.S. Reading the Wikipedia link, I find the answer to my question: No.
However, the warranty extension requirements look good to me -- having an older Subaru whose evaporative emmissions control system started to go wonky a bit after the 10 year mark. Something that can be bugger all difficult and expensive to diagnose and fix.
So ZEV's actually allow forms of emission that the PZEV may not. As long as it isn't an exhaust gas and one of the criteria exhaust gases.
f(x,y) = x^2 has a zero partial derivative.
PZEV's have zero evaporative emissions, and "super ultra low" tailpipe emissions
That's what the "partially zero" means - they have zero evaporative emissions.
It would be like calling it "partially zero cake" because it has zero sugar but some fat.
Also note that ZEV's do not take into account any of the emissions related to production of the fuel/electricity they use - that is outside the standard. So they may have more net emissions, they may have less.
Except it doesn't mean "partial zero." Instead, it refers to a "partial ZEV" (ie a partial vehicle).
The argument is that having a greater number of lower-emission vehicles[1] on the road has the same effect on air pollution as having a smaller number of zero-emission vehicles. So if those vehicles count as a partial ZEVs (for the purposes of the CARB ZEV Mandate), the same overall policy effect would be achieved.
[1] as you point out, legally they defined this as meeting the EPA SULEV emission requirements, plus having zero evaporative emissions