Seventeen states and the District of Columbia are CARB compliant states, meaning they enforce the California Air Resources Board’s vehicle emission standards instead of the looser federal baseline set by the EPA. Together they cover roughly 40 percent of the U.S. new-car market.1Alternative Fuels Data Center. Adoption of California’s Clean Vehicle Standards by State If you live in one of them, or you’re buying a car from outside one, the compliance status of your state controls what you can register, what parts you can install, and what you’ll pay to keep the car on the road.
The Full List
The states that have adopted California’s low-emission vehicle standards under Section 177 of the Clean Air Act are:1Alternative Fuels Data Center. Adoption of California’s Clean Vehicle Standards by State
- Colorado
- Connecticut
- Delaware
- Maine
- Maryland
- Massachusetts
- Minnesota
- Nevada
- New Jersey
- New Mexico
- New York
- Oregon
- Pennsylvania
- Rhode Island
- Vermont
- Virginia
- Washington
The District of Columbia has adopted them as well. California itself sets the rules these states follow, so it’s compliant by definition and is not counted among the seventeen.
Which Programs Each State Adopted
Not every CARB compliant state has adopted every California program. All seventeen enforce the low-emission vehicle (LEV) standards that cap tailpipe pollution from passenger cars and light trucks. Most have also adopted the zero-emission vehicle (ZEV) mandate, which requires manufacturers to sell a minimum share of electric and hydrogen fuel cell vehicles. Pennsylvania is the main exception: it follows the LEV emission standards but has not adopted the ZEV sales requirement.1Alternative Fuels Data Center. Adoption of California’s Clean Vehicle Standards by State
A smaller group has also adopted California’s Advanced Clean Trucks rule for medium- and heavy-duty commercial vehicles: Colorado, Maryland, Massachusetts, New Jersey, New Mexico, New York, Oregon, Rhode Island, Vermont, and Washington.1Alternative Fuels Data Center. Adoption of California’s Clean Vehicle Standards by State
Under Section 177, an adopting state must copy California’s standards exactly and adopt them at least two years before the model year takes effect. States can’t tweak the rules or create a “third vehicle” with locally modified standards, so a manufacturer only ever has to build cars in two flavors: federal and California.2Office of the Law Revision Counsel. 42 USC 7507 – New Motor Vehicle Emission Standards in Nonattainment Areas
How to Tell If a Vehicle Is CARB Compliant
Every new vehicle sold in the United States carries a Vehicle Emission Control Information (VECI) label, usually mounted in the engine compartment under the hood.3US EPA. Locating the Vehicle Emissions Label A CARB-certified vehicle will show a California emission category on that label: LEV, ULEV, SULEV, or ZEV. A vehicle certified only to federal standards will reference EPA compliance with no California designation.
The quicker check is the window sticker. Look for the phrase “50-state” on the Monroney label or in the vehicle listing. A 50-state vehicle meets California’s standards and can be registered anywhere. A “49-state” or “federal” certification means the car meets EPA rules only and generally cannot be registered as new in a CARB state.
This matters most when you’re buying from an out-of-state dealer or ordering a vehicle online. What’s legal to sell in Texas may not be legal to register in New York, and the discovery usually happens at the DMV counter after the money has changed hands.
Registering a Car From a Non-Compliant State
Moving a vehicle across state lines into a CARB state is where most people first run into these rules. The question is whether the receiving state treats your car as “new” or “used.”
California defines a new motor vehicle as one with fewer than 7,500 miles on the odometer when it’s first acquired by a resident. Below that threshold, a federal-only vehicle will be refused registration. Above it, the car is generally treated as used and is exempt from the new-vehicle certification requirement. Many Section 177 states apply similar thresholds, though the exact cutoff and paperwork vary.
The consequence of non-compliance is blunt: no plates, no title. Retrofitting a federal vehicle to meet CARB standards is rarely worth it, since it usually means replacing the catalytic converter system and engine control module with CARB-certified parts at a cost that often runs into thousands.
Inheritance, Divorce, and Military Exceptions
California and some Section 177 states carve out narrow exemptions. If you inherited a vehicle or received it through a divorce or legal separation decree, it can be registered in California even if it only meets federal standards and has fewer than 7,500 miles. You’ll need to certify the circumstances on the state’s designated form and submit documentation such as a death certificate, will, or court order.
Active-duty military relief exists in some jurisdictions, but it more commonly applies to taxes and fees than to emission standards. If you’re being transferred to a CARB state, check with the base legal assistance office before shipping your car.
Smog Checks After Registration
Registration is only the entry point. Most CARB states require periodic emission inspections to renew a registration. In California, smog checks are required every other year, though vehicles eight model years and newer are exempt. An inspection is also triggered whenever a vehicle changes ownership or is first registered from another state. Inspections typically cost somewhere between $30 and $90, depending on location and vehicle type.
If your car fails and the required repairs are expensive, most states offer a repair cost waiver. The framework varies, but you can generally obtain a time-limited registration waiver after spending a documented minimum on emission-related repairs without achieving a pass. That minimum commonly falls in the $450 to $1,200 range. The waiver usually lasts one or two years and the vehicle has to be retested when it expires.
Aftermarket Parts and Modifications
Installing performance parts or replacing emission components in a CARB state takes more care than it does in a federal-only state. Any part that affects the emission control system, including catalytic converters, exhaust headers, intake systems, and engine tuning software, must have a CARB Executive Order (EO) number to be legal.4California Air Resources Board. Aftermarket, Performance, and Add-on Parts The Executive Order certifies that CARB engineers evaluated the part and confirmed it doesn’t push emissions beyond certified levels.
Each EO-approved part carries a metal label with its Executive Order number. Having an EO number isn’t enough on its own. The part has to be approved specifically for your vehicle’s make, model, engine size, and emission certification tier. An EO-approved catalytic converter designed for one car will fail inspection on a different one. You can verify approval through CARB’s online aftermarket parts database or at a licensed smog check station.4California Air Resources Board. Aftermarket, Performance, and Add-on Parts
Tampering penalties reach past state smog check failures. Under federal law, removing, disabling, or rendering inoperative an emission control device carries civil penalties of up to $2,500 per violation for individuals, and up to $25,000 per violation for manufacturers and dealers.5Office of the Law Revision Counsel. 42 US Code 7524 – Civil Penalties Adjusted for inflation, the EPA has set the per-violation penalty for selling or installing defeat devices at $4,819 per device or per tampered vehicle in recent enforcement guidance.6United States Environmental Protection Agency. Enforcement Alert – Aftermarket Defeat Devices and Tampering These federal penalties apply everywhere, not just in CARB states.
What Changed in 2025
In June 2025, President Trump signed Congressional Review Act joint resolutions revoking EPA approval of three California waiver programs: the Advanced Clean Cars II regulation, the Advanced Clean Trucks rule, and the Omnibus Low NOx program. The White House stated the programs “are fully and expressly preempted by the Clean Air Act and cannot be implemented.”7The White House. Statement by the President
The Congressional Review Act also blocks the EPA from approving future waivers that are “substantially the same” as those disapproved. According to the White House, that bars future California waivers regulating greenhouse gas emissions or imposing electric vehicle sales mandates.7The White House. Statement by the President
When the EPA withdraws a California waiver, Section 177 states that adopted the same standards lose their authority to enforce them.8Library of Congress. California and the Clean Air Act Waiver – Frequently Asked Questions The revocations targeted the greenhouse gas standards and ZEV mandates specifically. California’s older waivers covering traditional criteria pollutants — the LEV, ULEV, and SULEV tiers that limit smog-forming compounds — were not addressed in these resolutions. The basic CARB certification tiers appear to remain in effect for now.
For a buyer, the practical takeaway is that ZEV sales quotas in Section 177 states are currently unenforceable. Manufacturers can still sell electric vehicles in those markets; the revocation removes the mandate, not the option. Availability will now track manufacturer decisions and market demand rather than regulatory quotas. Several states have signaled they will challenge the revocations in court, so the picture may shift again. If you’re making a purchasing decision that depends on ZEV rules or ACC II requirements, check with your state’s environmental agency or DMV first.
Before You Buy
In a CARB state, most new cars sold at franchised dealers are already compliant, because manufacturers ship 50-state certified inventory to those markets as a matter of course. The compliance question turns real in three situations: buying a used vehicle from a private seller in a non-CARB state, purchasing online from an out-of-state dealer, or moving into a CARB state from one that follows only federal standards.
Before you commit, check the VECI label under the hood for a California emission category and look for “50-state” language on the window sticker or the listing. If neither is there, assume the vehicle meets only federal standards and may not be registerable where you live. Five minutes with a flashlight costs less than a car you can’t drive.