As environmental regulations tighten across the U.S., California continues to lead the way with aggressive emission standards aimed at improving air quality. The latest regulation to impact commercial vehicle fleets is the Clean Truck Check, a program developed by the California Air Resources Board (CARB) and phased in beginning January 2023. Officially in effect at the start of 2024, this regulation introduces new compliance requirements for heavy-duty vehicles operating on California’s roadways.
What is the Clean Truck Check?
The Clean Truck Check stems from Senate Bill 210 (Leyva; Chapter 298, Statutes of 2019), which directed CARB to develop a comprehensive inspection and maintenance program for heavy-duty vehicles, known officially as the Heavy-Duty Inspection and Maintenance (HD I/M) regulation. Under the federal Clean Air Act, CARB is responsible for developing statewide strategies to reduce smog-forming and toxic pollutants emitted from mobile sources. Despite decades of regulatory progress, heavy-duty diesel vehicles over 14,000 pounds still account for the majority of on-road nitrogen oxide (NOx) and fine particulate matter (PM 2.5) emissions in California. While modern trucks are equipped with emissions-reducing technologies—such as diesel particulate filters and selective catalytic reduction systems—failures or malfunctions in these systems can lead to increased pollution levels and undermine air quality goals.
The Clean Truck Check is CARB’s response, and it aims to ensure that trucks operating in California maintain properly functioning emissions control systems throughout their use.
Approved in December 2021, the regulation is being rolled out in phases, but compliance requirements officially began in early 2024. This program is especially relevant for fleets with diesel-powered vehicles over 14,000 pounds gross vehicle weight rating (GVWR) that operate in California, regardless of where the vehicles are registered.
What Does the Regulation Require?
The Clean Truck Check combines periodic vehicle testing with other emissions monitoring strategies, such as on-board diagnostics (OBD) data collection and expanded enforcement tactics. To quickly identify vehicles emitting above legal thresholds and ensure timely repairs are completed.
Under the new rule, owners must:
- Register vehicles with CARB’s Clean Truck Check program.
- Undergo regular emissions testing and reporting. While most vehicles are subject to testing twice a year, older or non-OBD-equipped vehicles may be required to undergo quarterly testing.
- Maintain updated vehicle information, including adding or removing vehicles from the program.
Why Compliance Matters
When fully implemented, the regulation is expected to reduce statewide NOx emissions by more than 81 tons per day and PM emissions by 0.7 tons per day by 2037, resulting in over 7,500 avoided premature deaths. Ignoring Clean Truck Check requirements can result in fines, registration holds, or even enforcement actions that disrupt operations. Staying proactive with your emissions compliance not only helps you avoid penalties but also positions your company as a responsible leader of environmental standards. When fully implemented, this program is expected to deliver significant reductions in smog-forming emissions and carcinogenic toxic air pollutants, supporting both federal air quality mandates and healthier communities throughout California. As California continues to lead the charge on air quality initiatives, it’s likely other states may follow suit with similar programs.
How DISA Can Help
For many fleet operators, navigating CARB’s evolving regulations can be complex and time-consuming. With deep expertise in compliance and transportation solutions, DISA is prepared to support every step of your Clean Truck Check compliance process. From helping fleets register with CARB and ensuring that all required information is submitted accurately, to managing account setup and ongoing maintenance, DISA handles the administrative workload so you don’t have to. Our team also assists with vehicle management, including adding or removing vehicles from your fleet profile to maintain compliance with annual inspection requirements. As Clean Truck Check regulations evolve, DISA provides ongoing certification support to keep your vehicles up to date and operating legally.
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About DISA
Founded in 1986, DISA is the industry-leading provider of employee screening and compliance services. Headquartered in Houston, with more than 35 offices throughout North America and Europe, DISA’s comprehensive scope of services includes background screening, drug and alcohol testing, DOT & HR compliance, occupational health services, and I-9/ E-Verify. DISA assists employers in making informed staffing decisions while building a culture of safety in their workplace.