Recent revisions to the Advanced Clean Truck (ACT) rules by the California Air Resources Board (CARB) will effectively prohibit the sale of motorhomes in California and ten other states as early as 2025, according to RV industry representatives. Massachusetts, New Jersey, New York, Oregon, and Washington have all elected to adopt California’s ACT regulation beginning with the 2025 model year. Vermont has signed on to the initiative starting in 2026, followed by Colorado, Maryland, New Mexico, and Rhode Island in 2027.
While the rule does not specifically ban motorhome sales, there is a LOT to unpack about this regulation, how it’s going to be enforced, and why it’s such a big deal to the RV industry. While some aspects of the regulation are still being amended and a handful of legal challenges are still working their way through the courts, six states are going “all-in” starting January 1. Our collection of Frequently Asked Questions (and answers) will help dealers and manufacturers be prepared and know what to expect.
What is the Advanced Clean Trucks (ACT) Regulation?
The ACT regulation, adopted by the California Air Resources Board (CARB) in 2021, requires manufacturers of medium- and heavy-duty vehicles to gradually transition to primarily zero-emission vehicles by meeting sales standards for ZEVs as a percentage of their total sales This applies to all on-road vehicles with a gross vehicle weight rating (GVWR) of over 8,500 lbs., which includes vehicles from Class 2b to Class 8. By 2035, a significant percentage of vehicles sold in these categories must be zero-emission: 55% for Class 2b–3 vehicles, 75% for Class 4–8 trucks, and 40% for truck tractors.

The majority of the attention given to the ACT regulation by the RV industry has focused on Class A and Class C diesel motorhomes, but all medium- or heavy-duty vehicles built with internal combustion engines (gas and diesel) are subject to this rule. Specifically, any non-exempted on-road vehicle over an 8,500 lb. GVWR is covered by the regulation, including Class B motorhomes, because they traditionally exceed the 8,500 lb. GVWR that triggers compliance.
The other qualifier that triggers compliance is whether the vehicle qualifies as a new or a used motorhome. CARB defines a new vehicle as one with less than 7,500 miles on the odometer. Used motorhomes (those with more than 7,500 miles) are not covered by the regulation and can still be sold and registered in the participating states.
Why was ACT introduced, and what is its goal?
In an effort to try to stave off the effect of global warming – the effects of which scientists argue have negatively impacted the coastal U.S. with intense smog, severe droughts, rising sea levels (leading to coastal erosion), and prolific wildfires – the ACT aims to reduce greenhouse gas emissions produced by on-road vehicles. CARB states that this change will help reduce nitrogen oxides and other pollutants by limiting the volume of combustion engine chassis operating on roadways and contributing to this pollution. The ACT regulation supports California’s broader goals of achieving a 40% reduction in greenhouse gases by 2030 and transitioning to a cleaner, more sustainable transportation sector. This ACT also helps accelerate the shift to zero-emission vehicles (ZEVs) in medium- and heavy-duty vehicle markets.
If this is a California Rule, why are other states adopting it?
Section 177 of the Federal Clean Air Act grants a waiver to states that elect to adopt California’s motor vehicle emissions standards. The waiver exempts those states from needing approval from the U.S. Environmental Protection Agency to adopt rules that differ from the Clean Air Act. States that opt for the waiver are required (under Section 177) to adopt California’s regulations without revision or amendment. In this case, 10 other states have adopted the ACT regulation, with more states expected to follow suit.

How does ACT affect RV manufacturers and dealers?
By 2027, the ACT will cover the sale of new motorhomes in 11 states that, according to RVIA, make up 41% of motorhome sales in the U.S. The issue is whether motorhome manufacturers will be able to produce new motorhomes that can be sold in these 11 states. This is because the ACT regulation has established a system of ZEV credits that are designed to offset the production of medium- and heavy-duty vehicles with traditional internal combustion engines.
The credit system is designed to operate such that if a manufacturer produces a ZEV, they will earn credit that can be used to offset the production of a traditional internal combustion engine vehicle, and vice versa. Manufacturers are also free to trade and sell these “ZEV credits” to qualified members of the open market (currently limited to primary and secondary manufacturers of these medium- and heavy-duty vehicles).

So secondary manufacturers, like Winnebago, could theoretically purchase credits from another manufacturer to offset sales of their gas or diesel Class C motorhomes into any of these participating states, even though Winnebago might never have produced a ZEV to earn those credits. Although, it is expected that the cash value of these credits on the open market will be astronomical.
Are there any vehicle exemptions under the ACT?
Some vehicle categories are exempt, such as emergency vehicles, school buses, and military vehicles. Additionally, chassis manufacturers may use ZEV credits to offset deficits if they cannot meet the required ZEV sales percentages immediately. These credits can be traded, banked, or applied across vehicle types, including motorhomes.
Does the ACT really ban motorhomes?
Nothing in the regulation specifically bans motorhomes or prohibits their sale. The issue is there are no zero-emissions chassis currently rated for motorhomes. With no ZEV chassis available, chassis manufacturers have no way to earn ZEV credits to offset the production of traditional ICE chassis. As a result, some chassis manufacturers have hinted (or said outright) that they plan to limit or halt production of motorhomes to ACT states until there is a viable zero-emissions chassis rated for motorhomes.
This has set off alarms within the RV industry, with concerns that inventory of NEW motorhomes will be unavailable to dealers that sell in these 11 states. Motorhomes could still be delivered to dealers in these states, as long as the manufacturer certifies that they are intended for sale to an out-of-state end consumer who does not plan to register the motorhome in an ACT state. The burden of tracking the sale and registration of those motorhomes to make sure the end consumer doesn’t try to pull a fast one falls squarely on the chassis manufacturer – which is why many are choosing not to produce motorhomes to sell to those states at all.
There are no zero-emissions chassis options currently rated for motorhomes… Some manufacturers have stated that they plan to limit or halt production of motorhomes to ACT states.
So, what’s the big deal? The big deal is those 11 states account for 41% of all U.S. motorhome sales. If manufacturers stop producing motorhomes that traditionally use ICE chassis because they can’t produce them using a ZEV chassis (and earn ZEV credits), that strongly suggests there may be no new motorhomes for sale in these states. While the regulation doesn’t specifically ban motorhomes, the end result will effectively ban motorhome sales and deliver a significant blow to RV sales in those states. A potential blow that many dealers may not be able to offset. As Shakespeare’s Hamlet once said, “…aye, there’s the rub.”
Does CARB view this as a ban on motorhomes or have they made any exceptions for sale and registration of new motorhomes?
CARB has repeatedly denied that the regulation was ever intended to limit or halt the sale and registration of new motorhomes in ACT states. They point to provisions in the rule that allow motorhomes to be sold and registered in these states either through utilization of the credit market or by generating a carry-forward deficit that will have to be offset by credits within three years.
Those 11 states account for 41% of all U.S. motorhome sales… [the regulations] strongly suggest there may be no new motorhomes for sale in these states.
This deficit make-up period provision permits a chassis manufacturer that has an outstanding deficit after the end of a given model year (more traditional ICE vehicles than ZEVs) to make up that deficit within a consecutive three-model year period. This provision does not apply to motorhome manufacturers, who are considered secondary vehicle manufacturers. The three model year period begins following the ear in which a chassis manufacturer generated the deficit. For example, if there is an outstanding deficit by the end of the 2025 model year, the makeup period would apply to the 2026, 2027, and 2028 model years.
A caveat for chassis manufacturers who may want or need to exercise the deficit make-up period provision is a requirement to reduce their net deficit to below 30% by the end of the first and second years of the makeup period. If we revisit the hypothetical from above, the chassis manufacturer would need to reduce their net deficit balance, which would include the deficit from 2025 and any newly accrued deficit from 2026, to below 30% by the end of the 2026 model year. By the end of the 2027 model year, the manufacturer would need to again reduce their net deficit balance, which includes outstanding deficits from 2025, 2026, and 2027, to below 30%. The entire net deficit balance would need to be offset by the end of the 2027 model year. CARB considers this makeup period to be the breathing room the RV industry needs to get a ZEV chassis ready. However, it does little to incentivize chassis manufacturers to take action.
How is the ACT regulation being enforced?
Manufacturers who produce 500 or more medium- or heavy-duty vehicles to be sold in an ACT state will be required to report how many of those vehicles were ZEVs to show compliance with the graduated ZEV targets. In addition, manufacturers will be required to certify and level vehicles that have been delivered to each ACT state that are ZEVs. CARB adopted new vehicle labeling and reporting requirements for chassis manufacturers that will help regulators ensure that new vehicles registered in participating states are compliant with the ACT regulation. This would also apply to vehicles purchased in non-ACT states that were brought to ACT states to be registered.
Documentation for vehicles that are produced and delivered for sale in participating states must be kept by chassis manufacturers and secondary vehicle manufacturers for potential audit up to eight years from the end of the model year the vehicles were produced.
What challenges does ACT present for the RV industry?
Limited ZEV Chassis Options
As mentioned previously, there are few (if any) commercially available ZEV chassis suitable for motorhome applications, and little incentive for manufacturers to invest in developing one.
Increased Costs
Transitioning to ZEV manufacturing involves significant investment, which could lead to higher prices for end consumers. CARB has established grant programs to help offset costs, but they also point out that maintenance and upkeep over the life of the vehicle is far less costly. Compounding the cost issue is the proposition that chassis manufacturers may need to purchase ZEV credits to help offset sales of motorhomes using ICE chassis in the participating states.
Uncertainty in Supply
Manufacturers scaling down ICE production in response to ACT create uncertainty in RV production capacity. RV dealers will need to manage inventory and consider supply deficits when sourcing new motorhomes for sale in these 11 states.
Dealership Compliance
Dealers must carefully manage inventory to align with ACT’s requirements and ensure vehicles sold are compliant with CARB’s registration and labeling standards.
Are there benefits or opportunities for the RV industry?
Despite many challenges, the ACT does encourage innovation:
- Incentives and Funding: Programs like the Hybrid and Zero-Emission Truck and Bus Voucher Incentive help offset the upfront costs of ZEVs, providing financial support to manufacturers and dealers. But with 6 states implementing ACT in just a couple of weeks, the window of time left to build a viable ZEV chassis for motorhomes is running out.
- Market Differentiation: Early adopters of ZEV motorhomes may be best positioned to capture a niche market of eco-conscious buyers. That is, if the chassis manufacturers come up with a ZEV chassis that can be rated for motorhomes.
What does the future hold?
The ACT regulation will continue to influence RV production and sales in the 11 participating states. Manufacturers and dealers are encouraged to stay engaged with CARB, leverage the incentives, and prepare for a gradual transition toward ZEV-compatible RVs. Collaboration with policymakers and industry groups, like the RV Industry Association, will be essential to navigating these changes.
It’s going to be a bumpy transition to ACT compliance in these 11 states. Dealers that diversify their inventory and leverage the retained value of used motorhomes to meet local market demands will likely be the best positioned to navigate this transition while still maintaining customer satisfaction and market viability.
May the odds be ever in your favor.