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What is PZEV anyway?

It doesn't have anything to do with peace or electric vehicles. We'll dissect a Subaru Impreza Premium PZEV for answers to this conundrum of marketing, science, and politics. Mostly politics.

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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.

Who came up with this idea?
Why the California Air Resources Board (CARB), of course - our nation's top think tank of acronym-laden vehicle requirements (A-LVR) and politically correct environmental mumbo-jumbo (PCEMJ). Why did CARB come up with PZEV? Why.. because another mandate they laid down, this one involving the term ZEV, was impossible for many automakers to meet. So PZEV became a compromise.

You see, not long ago, the out of touch with reality, but very environmentally conscious board members at CARB decided that all auto manufacturers should be required to produce a zero emissions vehicle (ZEV) or else lose their ability to sell cars in California. After much discussion, in which several professors of automotive design and never-had-a-real-job engineering espoused the wisdom of this approach, the board approved the idea. When auto makers got wind of this, they complained.

The complaints got even louder when TZEV (transitional zero emissions vehicles, formerly AT-PZEV or Enhanced PZEV) vehicles were not included in this, but were given a special category all their own that would allow them to be transitional towards the ZEV requirement. After a lot of explanation, mostly using single-syllable words, to the CARB people, automakers were able to convince them that you can't just take any car and throw batteries in it and have it work right.

Of course, just creating exemptions wasn't easy or simple enough, so CARB had to come up with a complicated scheme. They'd just returned from an important conference in which Al Gore explained carbon credits and thought the plan a great one, so they adopted something just as convoluted for ZEVs. So an automaker that can amass enough ZEV credits to match a percentage of the sales they have in California can keep selling cars in California and if they happen to amass extras, they can sell those to other automakers that otherwise might not have made their ZEV credit requirements for the year.

In this way, the CARB members could continue to claim that they are helping the environment and somehow creating green jobs and manufacturers can continue selling the SUVs and crossovers that consumers really want just by getting those not rich enough to buy a Tesla or a Leaf to buy cheaper PZEV cars instead. In the end, it all worked out for everyone and only required the slaughter of an additional 100,000 or so trees to keep the paperwork flowing, resulting in the addition of a handful of green jobs because someone had to be hired to do all that wood chopping and paperwork filing.

Meanwhile, perfectly good cars like our little example Subaru Impreza Premium PZEV are sold with tax breaks in some states (of confusion) like California and consumers still get a perfectly good compact car capable of going to the lake on the weekend. It might not be as fuel efficient as it could have been were all those extra emissions compliance things not added in, but that's the price we pay to add new green jobs to the economy and ensure that the hundreds of millions spent by California taxpayers to keep CARB functioning aren't wasted on things like fixing the state's budget problems or improving schools.

Where the incredulous looks come in..
After explaining this to people, I usually got looks of disbelief. In a place where there is no state or county level income tax (and thus, gasp, no "rebates" for politicians to dangle) and where "mandates" are associated with alternative lifestyles; and where (despite the lack of regulation) we can still, somehow, see a lot more stars at night than most anyone else.. it's hard for people who live like that to understand the machinations of modern, sophisticated places like California where the regulatory rule of God is handed down in minutest detail to control life's every moment. You know, we being so backward and all.

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Stephen (not verified)    December 13, 2012 - 6:49PM

I searched "PZEV Subaru" to try to find out what the difference is between the PZEV models and the non-PZEV models. Instead I found this article written by some failed amateur author who managed to blog 13 paragraphs of adolescent filler. This goofy idiot tried to be informative and witty but failed on both counts.

Here's a tip: If you title an article with a question like "What is PZEV anyway?" and introduce it with a leader like "We'll dissect a Subaru Impreza Premium PZEV for answers", then it's a good idea to provide that answer for the reader instead of going off on stupe tangents about slaughtered trees and blah, blah, blah, California is dumb, blah, blah blah... When you don't bother to provide any actual, useful information in your writing, you come across as some laid-off mechanic who didn't know the answer to his own question and just wasted the time of whoever read his article.

Aaron Turpen    December 14, 2012 - 12:19AM

In reply to by Stephen (not verified)

I defined it exactly for what it is: a political construct. The entire "What is a PZEV then?" section gives the details and the rest of this article explains why it exists in the first place. In short, it's a bullshit "environmental feel good" designation that means nothing, but gives California an excuse to give tax breaks via bureaucratic control.

Here's a tip: before you criticize, actually READ.

Stephen (not verified)    December 14, 2012 - 12:36PM

In reply to by Aaron Turpen

I read your article. It was a waste of time.

I found an article written by someone who actually explains the difference between a PZEV Subaru and a non-PZEV Subaru. Hopefully it'll help those people who accidentally stumble across your article in the future.

Here's the link:

Auton Vaun (not verified)    December 18, 2016 - 7:42AM

In reply to by Aaron Turpen

Aaron, your defensive attitude and lack of pose is making me, and I'm sure many others, incredible uncomfortable. You should expect criticism with every article you write. When you react this way, instead of not reacting at all, you're insuring that your readers leave this article unhappy and dissatisfied with the material.

KL (not verified)    July 16, 2014 - 8:16PM

In reply to by BldrBob (not verified)


Not that it should come as a surprise to anyone that this article gets things wrong. PZEV is just about non-CO2 emissions, and does not noticeably affect fuel economy one way or the other.

Sebastian (not verified)    September 21, 2014 - 11:13PM

In reply to by KL (not verified)

Then why in Canada, a Subaru Outback, 2.5i , CVT transmission has a 40 mpg, compared to US model 2.5i, CVT @ 33 mpg Hwy? Almost 20% in fuel consumption? Same engine, same horsepower and torque, same car, where this big difference comes from? And look at Legacy model( Canada), and tell me what car (in USA), same size, gasoline engine and 4 wheel drive, will give you from a 2.5 engine 43 mpg?

Ronnie (not verified)    January 14, 2015 - 9:14AM

In reply to by Sebastian (not verified)

Canada uses the British Imperial Gallon (4.5 liters) whereas the US uses the US Gallon (3.8 liters). So the Canadian gallon is about 18% larger which accounts for the 18% increase in fuel economy.

BOB ASTOR (not verified)    September 1, 2016 - 10:54AM

In reply to by Sebastian (not verified)

The difference in MPG Canadian VS US is the use of Imperial Gallons VS US Gallons.
The U.S. liquid gallon and the U.S. dry gallon are different units defined by different means. The U.S. liquid gallon is defined as 231 cubic inches and equates to approximately 3.785 litres. One imperial gallon is equivalent to approximately 1.2 U.S. liquid gallons.
Hence your MPG would be 20% higher.

Charlie Peters (not verified)    July 26, 2014 - 5:55AM

Did Governor Brown choose a CA/DCA/BAR Chief who can find out if what is broken on a PZEV Smog Check failed car gets fixed? A Smog Check secret shopper audit would cut toxic car fleet impact 1500 tons per day while reducing cost by $billions.

Pete (not verified)    September 8, 2014 - 9:46PM

I actually find this article rather useful. Anyone can figure out what PZEV is all about, but trying to figure out if it is cost effective to shell an extra $200 for a PZEV vehicle is the big question. As I suspected from this article and many other's I have read, it seems to be somewhat of a scam to benefit the automakers and CARB and the consumer ends up paying for it. I will definitely not pay extra for a PZEV car as it gives me no cost benefit, and the reduced emissions are nearly negligible. If CARB employees really want to clean up the environment, they wouldn't be paid $150,000 plus dollars to buy their gigantic SUVs.

Andrew B (not verified)    May 24, 2015 - 11:17AM

Great explanation! Now it all just makes a little bit more sense. That last part though... reminds me of the old Communist Soviet Union (AKA California).

Charlie Peters (not verified)    June 22, 2015 - 2:42PM

* Do you want $2 Gasoline at the pump?

* Do you want clean air and water?

Ethanol waiver and elimination of E-85 flex fuel credit can cut our ozone & CO2 transportation pollution over 50%

Let’s improve performance of CA Climate change law AB 32 (Pavley) in 2015 for future generations

Charlie Peters (not verified)    August 28, 2015 - 4:48AM

I drive a 2015 ford PZEV

Out of about 20 sales and service dlr employees the only PZEV opinion was a detailer

About 2,000,000 Partial Zero Emissions Vehicles are on the road

The first PZEV was a 2000 model nissan

H (not verified)    December 4, 2016 - 10:38AM

My understanding is that the main difference in PZEV and non is the evaporative emissions as someone wrote. I did not read all these posts but wanted to give my take.
We have a 2008 Outback 2.5i Limited PZEV and the extended warranty alone is piece of mind as the converter alone is over 600 dollars. It has already been replaced once under warranty by subaru for Zero dollars at 80000 miles. Also the intake air box has a activated carbon screen to adsorb the fuel vapors emanating from the intake part of the engine. We get fuel vapors from injectors mostly and other unburned fuel sectors aka crankcase, cylinders a small bit. Also the injectors themselves are slightly modified to have more seating pressure i have been told, although i have not verified this one. Injectors do sometimes Drip, be fuel soaked at the tip and of course fuel evaporates (after all there job is to handle the fuel). In order to help lower emissions from millions of vehicles the automobile manufacturers and other EPA authorities such as CARB came to this brilliant (in my opinion) conclusion make a few simple changes. and extend the warranty. We were glade we had the option 8/)

Tom Winters (not verified)    December 10, 2016 - 3:19PM

All the hostility to low emissions and the State of California seems odd to me. The author lives in a state with a low population density so he doesn't like the idea of people trying to keep the air breathable in higher density states?

Paul crombie (not verified)    January 29, 2017 - 9:22AM

But what does it do? How does it work? How good is it? Does it do the job of knocking down emissions? I like the 150k warranty. Still confused here in Missouri.

Jim K (not verified)    February 1, 2017 - 9:25AM

I realize Aaron wrote this most of five years ago, but thank you Aaron. It answered the only question that I had; what the acronym stood for. I thought the rest was witty and informative. Aaron, I hope you have continued your blog/writing.

Owen Ford (not verified)    April 20, 2017 - 11:45AM

Two pages and I am none the wiser about what PZEV actually IS. But I do get the pleasure of hearing another blinkered car addict dodging responsibility for climate change. Awesome.

Daniel Cooper (not verified)    May 22, 2017 - 11:48AM

I am very concerned about the environment and climate change, and I really liked this article. There is way too much mumbo-jumbo and legalism in the environmental movement, and not nearly enough expertise and common sense. I live in Wyoming and drive a Forester and a Prius.