California Officially Bans Pre-2010 Diesel Trucks, Buses

Matt Posky
by Matt Posky

In 2008, the California Air Resources Board (CARB) approved legislation designed to curtail emissions from older trucks and buses operating within the state. Known as the “Heavy Duty Vehicle Greenhouse Gas Emission Reduction” measure, the law originally called for long-haul truckers to install specialized tires and aerodynamic devices on their trailers that improved fuel economy. However, it’s gone through numerous updates over the years, eventually making it illegal to even operate certain vehicles equipped with the wrong kinds of engines. The latest update bans any truck with a gross vehicle weight rating (GVWR) over 14,000 pounds using an engine manufactured before 2010.

These bans aren’t new. California began prohibiting older trucks and buses from hitting the road over a decade ago – and updates approved by CARB have kept pace to ensure vehicles utilizing older motors aren’t allowed to go anywhere. In 2020, the cutoff for diesel engines applied to anything manufactured prior to 2004. This year, the line has been drawn at 2010.

While the laws don’t technically prohibit anyone with a vehicle registered in another state from rolling through California with an older motor, the state will refuse the registration, renewal, or transfer of anything that doesn’t comply with the updated rules. However, the board has said it would also like to try and stop out-of-state vehicles from using older engines and has been working with the Environmental Protection Agency to enforce the rule on trucks not from California. Meanwhile, CARB has an enforcement unit of its own that will randomly audit in-state fleets, conduct inspections, and issue citations.

Back in 2022, CARB estimated that the latest rule change would impact roughly 200,000 buses and over 70,000 trucks currently in operation within the state. But it’s all allegedly for the greater good, as large trucks and buses are responsible for more per capita emissions than passenger cars.

"When we passed the regulations in 2008, it was to reduce community exposure of toxic air contaminants, it is 100 [percent] to protect public health," Gerald Berumen, a spokesman for the air resources board, told KCRA-TV in an interview.

The end goal is to keep the prohibition rolling until California’s 2035 diesel engine ban mandate comes into effect.

With combustion-engine bans becoming highly trendy in some parts of the country, pushback has likewise become commonplace. Critics have noted that these rules effectively force truck operators to purchase new engines. This disproportionately disadvantages independent operator-owners and smaller shipping companies with less money than the big boys. CARB has suggested compliance is easy, however, claiming that many operators and fleets have already complied with the new rules – with over 1.5 million vehicles being fitted with newer engines.

Not that they were left with much of a choice.

Additional criticisms focus on just how environmentally sound the scheme actually is. While swapping in a new motor should result in cleaner exhaust emissions, it also produces a lot of pollution upfront by requiring another motor to be manufactured as a replacement. This requires more raw materials, loads of shipping, and ultimately leads to a functional motor being scrapped. Some have also complained that CARB is out of touch and doesn’t accurately represent the needs of Californian citizens. Members of the board aren’t elected but appointed by the Governor and confirmed by the state Senate, typically with the 16-person air resources board making decisions on behalf of the citizenry.

But it’s also true that the topography of California leaves portions of the state in a bowl that traps more particulate matter. This is one of the reasons Los Angeles has had ongoing smog problems and regulatory boards are so aggressive. Though that may not be a sound justification for statewide engine prohibition.

Jalopnik has noted that there will be exemptions for the rule and TFLTruck posted the official list of compliance options earlier this month. For example, if you drive your big rig fewer than 1,000 miles per year (presumably because it’s a collectible or historic vehicle) then you’re off the hook entirely. Fleets can likewise install the latest particulate matter filters in their engines to buy themselves some time before having to purchase entirely new engines. Agricultural vehicles yielding low miles are also given some leeway. But the mileage restrictions have gotten more strict for 2023.

Still, if you happen to be driving a tractor-trailer or people-mover within the state as part of your profession, there’s likely no way around having to purchase a new motor. Granted, rebuilds and replacements are par for the course in the trucking industry. But these rules may mean you’ll be spending more sooner than you would have wanted to.

[Image: Vitpho/Shutterstock]

Become a TTAC insider. Get the latest news, features, TTAC takes, and everything else that gets to the truth about cars first by  subscribing to our newsletter.

Matt Posky
Matt Posky

A staunch consumer advocate tracking industry trends and regulation. Before joining TTAC, Matt spent a decade working for marketing and research firms based in NYC. Clients included several of the world’s largest automakers, global tire brands, and aftermarket part suppliers. Dissatisfied with the corporate world and resentful of having to wear suits everyday, he pivoted to writing about cars. Since then, that man has become an ardent supporter of the right-to-repair movement, been interviewed on the auto industry by national radio broadcasts, driven more rental cars than anyone ever should, participated in amateur rallying events, and received the requisite minimum training as sanctioned by the SCCA. Handy with a wrench, Matt grew up surrounded by Detroit auto workers and managed to get a pizza delivery job before he was legally eligible. He later found himself driving box trucks through Manhattan, guaranteeing future sympathy for actual truckers. He continues to conduct research pertaining to the automotive sector as an independent contractor and has since moved back to his native Michigan, closer to where the cars are born. A contrarian, Matt claims to prefer understeer — stating that front and all-wheel drive vehicles cater best to his driving style.

More by Matt Posky

Join the conversation
3 of 110 comments
  • Joh65690876 Joh65690876 on Jan 23, 2023

    One medium sized California forest fire will produce more particulate matter in 2-3 days than all of the diesel fuelled trucks and buses produce in a year.

    • EBFlex EBFlex on Jan 23, 2023

      Context and perspective is not allowed here

  • Joh65690876 Joh65690876 on Jan 25, 2023


  • VoGhost Key phrase: "The EV market has grown." Yup, EV sales are up yet again, contrary to what nearly every article on the topic has been claiming. It's almost as if the press gets 30% of ad revenues from oil companies and legacy ICE OEMs.
  • Leonard Ostrander Daniel J, you are making the assertion. It's up to you to produce the evidence.
  • VoGhost I remember all those years when the brilliant TTAC commenters told me over and over how easy it was for legacy automakers to switch to making EVs, and that Tesla was due to be crushed by them in just a few months.
  • D "smaller vehicles" - sorry, that's way too much common sense! Americans won't go along because clever marketing convinced us our egos need big@ss trucks, which give auto manufacturers the profit margin they want, and everybody feels vulnerable now unless they too have a huge vehicle. Lower speed limits could help, but no politician wants to push that losing policy. We'll just go on building more lanes and driving faster and faster behind our vehicle's tinted privacy glass. Visions of Slim Pickens riding a big black jacked up truck out of a B-52.
  • NotMyCircusNotMyMonkeys dudes off the rails on drugs and full of hate and retribution. so is musky.