For Vehicles Subject to Semiannual/Annual Testing

The California Air Resources Board (CARB or Board) has posted a guidance document for vehicle owners with updated information on the expected start date of the Clean Truck Check periodic compliance testing in 2024 and projected compliance deadlines for vehicles subject to semiannual (twice per year) testing. Information is also provided for certain vehicles required to undergo compliance testing only once per year.

It augments previous guidance released in late June 2023 on CARB’s plans to implement a three-month open reporting period projected to run from October 1, 2023, to December 31, 2023. To access the previous guidance, please visit the June 2023 Guidance to Vehicle Owners on Upcoming Requirements website.

Background

Heavy-duty vehicles with gross vehicle weight ratings (GVWR) greater than 14,000 pounds continue to be major contributors to statewide mobile air pollution, even though this sector only makes up about three percent of the total on-road vehicles operating in California. To limit excess emissions from these heavy-duty vehicles, the Heavy-Duty Inspection and Maintenance regulation was finalized in 2022 requiring vehicles above 14,000 pounds GVWR operating in California to undergo periodic emissions control equipment inspections to ensure they are operating properly.

Vehicles Subject To Semiannual Testing

Nearly all diesel and alternative fuel heavy-duty vehicles that operate in California are subject to semiannual testing.  To see when your vehicle’s initial periodic test is projected to be due, refer to the semiannual testing link above. Affected vehicles include hybrid trucks and buses, commercial vehicles, privately-owned vehicles, government vehicles, and vehicles registered outside of California. For information on vehicles that are exempt from Clean Truck Check, please refer to the Fact Sheet: Heavy-Duty Inspection and Maintenance Program: Background and Requirements.

Key highlights from the “Guidance to Vehicle Owners on 2024 Periodic Testing Requirements for Vehicles Subject to Semiannual Testing” are as follows:

• CARB staff projects that periodic testing requirements will start for vehicles on their first compliance deadline on or after July 1, 2024.
  • A passing compliance test will be required to be submitted to CARB within the 90 days before a vehicle’s compliance deadline.
• For 2024 only, all vehicles subject to semiannual compliance testing will be required to test and submit results to CARB one time.
  • Starting in 2025, these vehicles will have semiannual compliance deadlines (two each year, one every six months).

Vehicles Subject To Annual Testing

California registered motorhomes and heavy-duty vehicles used exclusively in agricultural operations (California registered and non-California registered) are required to undergo periodic compliance testing annually, rather than semiannually. To see when your vehicle’s initial periodic test is projected to be due, refer to the annual testing link above.

Key highlights from the “Guidance to Vehicle Owners on 2024 Periodic Testing Requirements for Vehicles Subject to Annual Testing: California Registered Motorhomes and Agricultural Vehicles” are as follows:

• CARB staff projects that periodic testing requirements will start for California registered motorhomes and agricultural vehicles in 2024.
  •  A passing compliance test will be required to be submitted to CARB within the 90 days before a vehicle’s compliance deadline.