Clean Truck Check Program – Heavy-Duty Inspection and Maintenance (HD I/M) Initiative

The Clean Truck Check, previously referred to as the Heavy-Duty Inspection and Maintenance Program, aims to ensure heavy-duty vehicles, such as trucks, buses, and motorhomes, are maintained to operate cleanly and efficiently. A major update under this initiative is that the Clean Truck Check regulations now apply to all trucks operating within California, regardless of whether they are registered in the state.

Reporting Requirements for Clean Truck Check

Under the program, the California Air Resources Board (CARB) mandates that vehicle owners complete initial fleet reporting and pay a compliance fee. This can be managed via CARB’s Clean Truck Check reporting database, where further details on California-specific requirements can also be accessed.

Scope of Regulation

The Clean Truck Check, or Heavy-Duty Inspection and Maintenance Program, applies to most non-gasoline vehicles, including diesel-powered ones, with a gross vehicle weight rating (GVWR) of 14,000 pounds or more operating within California. In addition to the reporting requirement, a $30 fee per vehicle must be paid each year.

Failure to comply with these requirements can result in CARB placing a registration hold with the DMV on non-compliant vehicles, potentially preventing their legal operation within California.

Program Timeline and Phases

The Clean Truck Check regulation was approved by CARB in 2021, with the following implementation phases:

• Phase 1 began on January 1, 2023, with CARB introducing Remote Emissions Monitoring Devices and roadside monitors to identify high-emitting vehicles, which are then flagged for testing.
• Phase 2, which started on October 1, 2023, focuses on database reporting, requiring vehicle owners to report fleet information through the Clean Truck Check database.
• Phase 3, set to commence on January 1, 2025, will require biannual emissions testing for heavy-duty vehicles. For California-registered vehicles, emissions tests will align with DMV registration deadlines, and results must be submitted within 90 days of the compliance date. Testing may begin in October 2024 for certain vehicles.

CARB Compliance Requirements and Testing Frequency

Starting in 2025, vehicles subject to this program will need to undergo emissions testing every six months, with passing test results submitted within 90 days before their compliance deadline. For on-road agricultural vehicles and motorhomes, testing is required annually, and results must also be submitted within the 90-day compliance window.

Database Reporting for Fleet Compliance

In 2024, vehicle owners or their designees must register in the Clean Truck Check database to comply with the HD I/M regulation, paying a $30 per vehicle compliance fee. This may include fees for the 2023 period.

Notices and Penalties

CARB has implemented Roadside Emissions Monitoring Devices (REMD) that may result in a Notice to Submit to Testing (NST) if high emissions are detected, potentially leading to enforcement actions, fines, or citations. To maintain compliance, vehicle owners are encouraged to order their emissions compliance test under the Clean Truck Check program.

DMV Registration Holds for Non-Compliance

As of 2025, registration holds may also be applied by the DMV for vehicles not meeting Clean Truck Check compliance requirements. To learn more about the program and ensure compliance, visit the Clean Truck Check (HD I/M) portal.