Wednesday, September 27, 2023


Will California’s diesel law affect you as an RVer?

By Russ and Tiña De Maris

Smog over Los Angeles
Photo by DAVID ILIFF. License: CC BY-SA 3.0

Back in 2008, California’s controversial California Air Resources Board (CARB) formulated new regulations for heavy (over 14,000 pound gross vehicle weight) diesel-fired trucks and buses. To clear the Golden State air for “health” reasons, CARB mandated such rigs registered in California begin to meet certain particulate emissions standards. It was a phased-in approach: In 2012, particulate filters were mandatory; and in 2015, older rigs were to start being either replaced outright or have 2010 or newer engines installed.

While there were big fines attached to those who failed to comply, as of a year and a half ago only about 70% of all rigs were in compliance. CARB inspectors said it was common to find a truck owner who’d in essence tell them: “If you catch me, then I’ll comply.” CARB responded, putting scofflaws on notice that effective January 1, if a rig isn’t in compliance with the law, then its owner will no longer be able to get a vehicle registration.

A concerned reader wrote us about this matter. While it’s true few RVers would have a tow vehicle that hits the 14,000-pound weight designation, there are plenty of California RVers who have motorhomes or bus-conversions that would come under that description. What does this new crackdown mean for them? Will scores of motorhomes and “schoolies” suddenly get locked down?

The requirements, titled “Truck and Bus Regulation,” say this: “The Truck and Bus Regulation affects individuals, private companies, and Federal agencies that own diesel vehicles with a Gross Vehicle Weight Rating (GVWR) greater than 14,000 lbs. that operate in California.” Broken down, come January, any diesel truck or bus in that weight class and built before 2002 must be off the road, or have a 2010 or newer engine installed. In 2021, rigs older than 2007 are off the road; and in 2023, anything older than 2010 is likewise grounded.

But what about motorhomes? Is a Class-A motorhome on what could be considered a truck chassis under this restriction? CARB provided us with a copy of the specific rule*. Under the title “Exemptions,” item number 10 reads, “Motor homes for non-commercial private use.” Evidently, as long as your motorhome is classified as a recreational vehicle, clearly shown on your DMV registration as a motorhome, you’re in the clear with no need to upgrade engines or get off the road.

Interestingly, item 12 under this same exemption section reads, “Trucks with a GVWR of 19,500 lbs or less with a pick-up bed used exclusively for personal, non-commercial, or non-governmental use.” So, provided your bigger, heavy-class towing unit includes a “pick-up bed,” you’re also in the clear. We have seen a few enterprising souls who have used a semi-truck to pull a large fifth-wheel. Unless we’re reading the law incorrectly, older truck owners are in a pickle. An expensive engine change or a new hauler appear to be a non-arguable case.

Which takes us back to bus conversions. We’ve seen plenty of beautiful “retired” Greyhounds and truly imaginative school bus conversions. What’s the story there? CARB’s public information office tells us for folks who own these special conversion units, life (and exemptions) may not be as easy. Karen Caesar, a board information officer, warns, “Some vehicles will be difficult for the DMV to identify as compliant with the Regulation. CARB has developed the Excluded Diesel Vehicle Reporting (EDVR) System as a tool to assist vehicle owners who have had (or will have) their DMV vehicle registration denied inadvertently. This includes vehicle conversions to motorhomes.”

One can hope that unlike 2001: A Space Odyssey’s HAL 9000 computer, EDVR will be a bit easier to deal with. But any time a bureaucracy gets involved, somehow it just feels like it’ll get complicated. “Documentation to support this claim is required,” warns Caesar. “Submitting documentation that is complete, legible, and accurate at least a month before your registration due date is the best way to avoid the need to pay a fee to DMV for a temporary registration permit.”

If your RV is a conversion, it’s best to get your ducks in a row soon. The request and paperwork is to be sent to EDVR through the internet. Here’s a link to the system. Part of the process includes taking pictures of required documents and, of course, “Submitting documentation that is incomplete, illegible, and/or inaccurate will result in this request being rejected,” warns the regulating agency. Go slow, and be prepared for frustrations. Remember Hal’s words? “Look Dave, I can see you’re really upset about this. I honestly think you ought to sit down calmly, take a stress pill, and think things over.”

And what about those who visit California in a truck or bus that would be otherwise undrivable under this regulation? Happily, the California regulation would have no teeth to shut them down. At least for now. What about the future? We asked EDVR to give us his prognostication. His reply?  “I’m sorry Dave, I can’t do that.”

*Title 13, California Code of Regulations, section 2025 of Article 4.5. “Regulation to Reduce Emissions of Diesel Particulate Matter, Oxides of Nitrogen and Other Criteria Pollutants from In-Use Heavy-Duty Diesel-Fueled Vehicles.”


Russ and Tiña De Maris
Russ and Tiña De Maris
Russ and Tiña went from childhood tent camping to RVing in the 1980s when the ground got too hard. They've been tutored in the ways of RVing (and RV repair) by a series of rigs, from truck campers, to a fifth-wheel, and several travel trailers. In addition to writing scores of articles on RVing topics, they've also taught college classes for folks new to RVing. They authored the book, RV Boondocking Basics.


  1. We’re screwed….again…..

    Anybody got land in a state with SANE Smog Laws? Reply here or at my email, Thanks, Patrick Young

    (I got 2 Kohler DIESEL gensets (adios) a Ford F7000 with a CAT (grounded tomorrow)…

  2. In the early 1980’s I was an electronics technician that got to travel to most major cities in the US and one of those cities was LA. I can remember to this day descending through the thick black smog cloud that covered LA. After spending several days breathing in that smog I could feel the effect on my lungs.
    Like most of you I believe it is our governments job to look out for the health and welfare of its citizens and in this one case I have to admit that I think CA has done a good job.
    A test anyone can make is place yourself in a garage with a running 1960 or so auto than repeat the test with a 2012 or later and you will truly understand the significant improvement in later model emissions.
    I have no love for CA, I would not live there and I have no desire to travel there but I do like breathing clean air and I do get pissed off when I see old commercial trucks belching black smoke.

    • In 1971 I was in the Navy. My ship put into Long Beach and the chaplain organized a tour to Disneyland for the young sailors (and the young at heart.) I looked at the air over Los Angeles and decided I didn’t want to see Disneyland badly enough to go breath that dirty brown/green air. In 1983 I returned on a visit and have been back several times since and the air is much, much better. Those dratted regulations really did work.

  3. I am forever amazed that folks do not understand the health consequences of dirty diesel. A bold statement and a controversial one no question but if it was up to me I’d outright ban any vehicle diesel or not that doesn’t rise to a very high air quality rating. This is 2019, in case anyone needs reminding!!!

    For the life of me I do not get why some folks think its their “right” to make the bloody planet their ashtray – to hell with anyone else. I agree with the “diesel nuts” I also avoid the border of the “nuts and fruits”, like I do if possible the inconsiderate fool running his diesel next to me for an hour filling my rig with poison, while I try to enjoy the view over my morning coffee & Wheaties.

    • Just a note. Today’s diesel is cleaner than gasoline. And yes, the inconsiderate people who run their engines are annoying. We don’t as we know it isn’t necessary. We have a 2002, so not sure why those with newer MH’s still do that.

  4. There are a few states I’ll never visit again. CA is at the top of the list. I’m sur they will not miss me as sane people are not wanted.

  5. We too, NEVER cross the border into CA. And this may have a bearing on why thousands are moving OUT of CA every year.

  6. It makes NO DIFFERENCE to me since I will NEVER, let me repeat, NEVER travel in the “Land of Fruits and Nuts” (California) . They have to many incredibly STUPID Laws to know about or even try to comply with!

    Thank GOD we have a choice to NOT visit or Spend our hard earned money in this Ridiculous State!

    • Californian here. That ship has sailed. It’s been around for awhile. Lots of unhappy people. Would love to leave the state, just not practical for us.


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