California Clean Truck Check and Fee by Jan 31, 2024, Who is Required?

California Clean Truck Check and Fee by Dec 31, 2023, Who is Required?

The Heavy-Duty Inspection and Maintenance (HD I/M) regulation is a new program starting in 2023 to ensure polluting, poorly maintained heavy-duty vehicles operating in California are quickly identified and repaired.

CARB is at it again.

The California Air Resources Board (CARB) is trying to reduce the health effects caused by heavy-duty diesel vehicles greater than 14,000 pounds that contribute most of the on-road NOx and PM 2.5 emissions in the state. 

To ensure that vehicles’ emissions control systems are properly functioning when traveling on California’s roadways, CARB approved the Clean Truck Check program that combines periodic vehicle testing requirements with other emissions monitoring techniques and expanded enforcement strategies to identify vehicles in need of emissions related repairs and ensure any needed repairs are performed.

Previous efforts include regulations and programs for new engine standards, manufacturer warranties, and durability requirements for emission control components; in-use truck rules to accelerate fleet turnover; and incentive programs to promote innovative low- and zero-emitting technologies.

Let’s look at what the Clean Truck Check program requirements are and the upcoming deadline for compliance.

What is California’s Clean Truck Check program?

Simply, the state is implementing a heavy duty vehicle inspection and maintenance program.

While modern heavy-duty diesel vehicles are equipped with aftertreatment systems (like diesel particulate filters for controlling PM and selective catalytic reduction) for cutting NOx emissions, if these components malfunction, this may result in emissions increases that can stall efforts to achieve clean, healthy air in California’s communities.

The Clean Truck Check will ensure heavy-duty vehicles operating in California are:

  • Well-maintained
  • Repaired rapidly when needed, and
  • Promote a level playing field for the businesses that operate them

They will do this through an integrated strategy combining:

  • Roadside emissions monitoring to screen for potential high-emitting vehicles,
  • Improved emissions testing procedures using on-board diagnostics data,
  • Emissions checks and data reporting at required intervals, and
  • Compliance verification requirements for freight contractors, seaports, and railyards

When fully implemented, the regulation is projected to cut statewide NOx emissions by over 81 tons per day and PM emissions by 0.7 tons per day in 2037. Together, these emissions reductions will result in over 7,500 avoided premature deaths.

Who is required or exempt from the Clean Truck Check program?

Nearly all diesel and alternative fuel heavy-duty trucks and buses with a power unit only vehicle weight rating over 14,000 pounds that operate in California must comply.

This includes hybrid trucks and buses, commercial vehicles, privately-owned vehicles, government vehicles, and vehicles registered outside of California.

However, there are several vehicles that are exempt from the regulation:

  • Zero-emission vehicles
  • Military tactical vehicles
  • Emergency vehicles
  • New vehicles with engines certified to the most stringent optional, NOx standard (only for the first four years of program implementation)
  • Motorhomes registered outside of California
  • Vehicles operating under an experimental permit
  • Historical vehicles

Roadside emissions monitoring started January 2023

The program began in January 2023 with the use of roadside emissions monitoring devices (REMD) to screen for vehicles that may have high emissions.

Vehicles flagged as potential high emitters may be required to undergo follow-up vehicle compliance testing to ensure they are operating with properly functioning emissions control systems.

If your vehicle is identified as a potential high emitter through REMD, you will receive a Notice to Submit to Testing (NST) from CARB. Upon receival, you will have 30 calendar days to submit to CARB a passing HD I/M compliance test performed by a HD I/M tester.

  • OBD equipped vehicles are required to undergo a scan of the engine’s OBD data using a CARB-validated OBD test device. Diesel vehicles and diesel hybrids with 2013 and newer model year engines have OBD systems. For alternative fuel vehicles, 2018 and newer model year engines have OBD systems.
  • Non-OBD vehicles, i.e., those that don’t meet the engine model year requirements above, are required to undergo a smoke opacity test and a visual inspection of the vehicle’s emissions control equipment, referred to 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 PSIP.

CARB published a list of HD I/M testers with contact information that offer for-hire testing services, which may include mobile services, on CARB’s HD I/M webpage at:

Be sure to follow the instructions in the letter you receive from CARB and don’t wait until the last day to get your vehicle tested and submit test results to CARB.

Once CARB determines your vehicle is compliant, there is nothing more you will need to do in response to the NST.

Compliance verification and registration deadline by January 31, 2024

By January 31, 2024, vehicle owners are required to:

  • Create owner accounts in CARB’s HD I/M database,
  • Verify the vehicles in their fleets (website allows bulk vehicle upload or individual units), and
  • Pay the first annual compliance fee for each vehicle ($30 per vehicle)

Once $30 annual fee is paid, the system will alert you when the periodic testing is due.

Beginning in 2025, the fee must be paid annually by the registration expiration date for CA DMV.

The HD I/M database will incorporate vehicle data from existing CARB databases and from DMV data. Many vehicle owners only will need to check that the vehicle data is correct, while others may need to input the data manually.

Also, ONLY vehicles with 2010 or newer engines are permitted to register – pre-2010 vehicles are not permitted to travel in California.

If a business adds or removes a vehicle from their fleet after creating an account, vehicle owners must update vehicle information within 30 calendar days of a transaction to add or remove a vehicle.

Once enforcement begins, vehicle owners that don’t comply with these requirements may be cited for non-compliance and/or have their DMV vehicle registrations blocked.

Out of state vehicles must follow the deadline below based on the last number of the VIN

Last Number of VIN0123456789
2024 Compliance Deadline MonthOctNovDecJulyAugSeptOctNovDecJuly

To note, this is separate from the CARB TRUCRS requirements.

Periodic Vehicle Testing requirements start in 2024

Starting in 2024, CARB staff should start periodic testing for vehicles on their first compliance deadline on or after July 1, 2024.

  • For the 2024 calendar year only, vehicles subject to semiannual compliance testing will be required to test only once.
  • Starting in the 2025 calendar year, these vehicles will have two compliances deadlines each year, one every six months.

To be deemed compliant with Clean Truck Check, a passing compliance test from an applicable vehicle must be submitted to CARB within the 90 days before a vehicle’s compliance deadline.

For example, if a vehicle’s periodic compliance deadline in 2024 is November 30, a passing compliance test would need to be submitted to CARB’s Clean Truck Check database system between September 1, 2024, and November 30, 2024.

The vehicle’s 2024 annual compliance fee also would be due by the compliance deadline.

The Clean Truck Check database system will provide vehicle owners and fleet managers access to the schedule of their vehicles’ upcoming periodic compliance testing deadlines and compliance fee payments.

Other HD I/M requirements after compliance enforcement starts

Freight contractors and brokers must verify that heavy-duty vehicles they contract with for services are in compliance with the HD I/M regulation.

This also includes public agencies that contract for heavy-duty truck services.

Additionally, seaport and railyard facilities must verify compliance with the HD I/M regulation for vehicles that enter their facilities.

If you have further questions, please email CARB staff at They generally respond within three to five business days.

Questions about DOT Compliance, Licensing, Audits, Programs, etc.?

Our DOT Specialists are here to help!

Related news

Monthly Newsletter

February 21, 2024

Watch the most recent episode for a Quick Trucking News Update

What are you searching for?

Related Services

Is DOT Compliance your Top Priority?

Our DOT Compliance Programs ensure it is your top priority and keeps your business running.

Subscribe to our Monthly Newsletter

Receive the latest transportation and trucking industry information about FMCSA and DOT Audits, Regulations, etc.

Social Media

Related news

Monthly Newsletter

February 21, 2024

Watch the most recent episode for a Quick Trucking News Update