What is PZEV anyway?
It's likely you've seen the term "PZEV" on a vehicle recently. You might have even assumed it was some kind of hybrid or green vehicle. If you guessed the latter, you'd be close.
The "EV" in the term PZEV doesn't stand for "electric vehicle" as we've come to know the acronym. Instead, PZEV stands for Partial Zero Emissions Vehicle. It's a sort of mashup category of cars created almost entirely through politics.
Recently, the question came to the fore when I was test driving a 2012 Subaru Impreza Premium PZEV. The Impreza features a nice, shiny little symbol on the trunk with PZEV sprouting a leaf. When talking to people about this neat little car, they inevitably assumed that this symbol meant it was a hybrid-electric of some kind. After explaining what it really meant a few times (often to dumbfounded expressions), I realized that most people aren't really familiar with the term or what it's for. And many find it incredulous once they do find out about it. At least, people who live in Wyoming do. I didn't ask anyone in Jackson Hole (Wyoming for "California") about it, honestly.
What is a PZEV then?
A partial zero emissions vehicle has a PZEV engine or drive train that meets or exceeds specific requirements set forth by the State of California. It's almost 100% politically-created since the criteria have as much to do with warranties and getting around other California mandates as they do with emissions requirements.
The Subaru pictured, for instance, is a compact car that gets 27mpg city and 36mpg highway and sports all wheel drive - which where I live is a pretty good package all together given the amount of highway and semi-offroad (dirt, gravel) driving we do out here. For all that, the Impreza PZEV puts out 90% less emissions than its equivalent counterpart, meaning it meets federal super ultra low emission vehicle (SULEV) standards.
(Not just super, but super ultra.)
That alone doesn't make it a PZEV, though. To meet that distinction, it must be a SULEV and have zero evaporative emissions from its fuel system and have a 15 year/150,000 mile warranty on its emission control components. Having all of those things makes a car PZEV special.