The rule says truck owners must do emissions tests and pay yearly fees if they drive in California. The EPA did not agree with the rule for trucks from other states, but California will still enforce it in the state. On January 27, the EPA said it does not fully approve California’s Heavy-Duty Inspection and Maintenance (HD I/M) regulation for trucks registered outside California.
This rule is also called the Clean Truck Check or ‘smog check.’ Since 2023, it has required truck owners in California to undergo emissions testing and pay a fee if their trucks weigh over 14,000 pounds and use fuels other than gasoline. The fee started at $30 and changes with inflation. As of January 1, 2026, it is $32.13.
Trucks with special testing systems can be checked using that data. Older trucks are tested by visual inspection and smoke testing. Truck owners must carry a certificate to show they follow the rule and show it to officials if asked. California sent its Clean Truck Check rule to the EPA as part of its plan to meet air quality standards. The EPA then checks if the plan meets federal law. If the EPA approves a state plan, the rules become federal law.
California’s Air Resources Board sent the rule to the EPA on December 14, 2022. The EPA partly agreed and partly disagreed with it on January 27. The EPA said the rule is okay for trucks registered in California, but not for trucks from other states or countries.
EPA Administrator Lee Zeldin said the EPA will not allow California to impose rules on the entire country. He said that expensive rules could raise prices for everyone. He said people want lower costs, not extra rules from California. California’s Air Resources Board said it will still enforce the rule in California, even though the EPA does not fully support it. They said all trucks in California must follow the same rules.
The EPA replied that, without its approval, California cannot require trucks from other states to comply with the rule. The EPA said California cannot make rules for the whole country. The EPA says California can still use the rule inside the state. The EPA will not punish California because the rule is not required by federal law. So, California’s rule stays in place inside the state, even though the EPA does not fully approve it.
For the EPA to approve a state rule, it must ensure that no other laws prevent the state from implementing it. The EPA said California did not prove it is allowed to make rules for trucks from other states or countries that drive through California. The EPA said the rule is unfair to truckers from other states because it forces them to pay more for benefits that mostly benefit California.
The EPA said California did not have to make the rule apply to trucks from outside California. California could have just enacted stricter rules for trucks registered there. The EPA said California chose to add trucks from other places, but it was not needed for the rule to work in California.
If the EPA had approved the rule, truckers from all over would have to follow it when driving through California. Many trucks cross California every year, and failing to follow the rules could mean big fines. The EPA said that if it agreed, the rule would become federal law, and all heavy trucks in the U.S. might have to pay more to comply. The EPA also said that requiring trucks from other countries to comply with the rule could violate U.S. laws governing foreign relations.
