CARB Clean Truck Check Compliance Begins January 1, 2024

Beginning on January 1, 2024, all heavy-duty vehicles operating in California will need proof of compliance with the California Air Resources Board’s (CARB) Clean Truck Check regulations to continue operating in the state. Vehicles must be registered in the Clean Truck Check database by December 31st, 2023, which is found here:

Clean Truck Check, formerly known as the Heavy-Duty Inspection and Maintenance Program, was approved by CARB in 2021 to test heavy-duty vehicles’ emissions control systems for proper operation. Nearly all diesel and alternative fuel vehicles over 14,000 pounds gross vehicle weight rating that operate in California, including personal vehicles, will be required to comply.

Clean Truck Check is being implemented in three phases.

Phase 1, which started January 1, 2023, began with the deployment of Remote Emissions Monitoring Devices (REMD) to monitor the exhaust emissions of passing heavy-duty vehicles and flag potential high emitters that may receive a Notice to Submit to Testing (NST).  NST’s require vehicle owners to submit a passing compliance test to CARB after any necessary emissions-related repairs are made within 30 days of receipt of the notice.

Phase 2, which started October 1st, 2023, requires vehicle owners who are subject to the program to enter their vehicles in CARB’s Clean Truck Check database and pay an initial annual compliance fee of $30 per vehicle by December 31st, 2023.  Starting January 1, 2024, all trucks driving in California will need proof of compliance with these requirements to continue operating in the state. Operating in California without registration in the compliance database could result in violations from CARB and/or the CHP.

Phase 3, which starts January 1, 2024, and applies to all compliance deadlines after July 1, 2024, requires heavy-duty vehicle owners to conduct periodic emissions testing on their vehicles, similar to California’s Smog Check program for cars.  Per CARB, 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).  In three years, this testing requirement will jump to four times a year. 

For California-registered vehicles, the due dates, called compliance testing deadlines, are linked to each vehicle’s DMV registration expiration/renewal date. Passing test results may be submitted up to 90 days before a compliance deadline (so, as early as April 2024).

Testing requirements vary based on whether the vehicle is equipped with onboard diagnostics (OBD).  OBD-equipped vehicles are required to undergo a scan of the engines’ OBD data using a CARB-validated OBD test device. Non-OBD vehicles are required to undergo a smoke opacity test and a visual inspection of the vehicle’s emissions control equipment, referred to in this program as the Vehicle Emissions Control Equipment Inspection. The smoke opacity test is the same SAE J1667 snap acceleration smoke inspection used to comply with CARB’s Periodic Smoke Inspection Program (PSIP).

Clean Truck Check program information can be found here:

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