Air Plan Revisions; California; Heavy-Duty Vehicle Inspection and Maintenance Program

<RULE> ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Part 52</CFR> <DEPDOC>[EPA-R09-OAR-2025-0061; FRL-12606-02-R9]</DEPDOC> <SUBJECT>Air Plan Revisions; California; Heavy-Duty Vehicle Inspection and Maintenance Program</SUBJECT> <HD SOURCE="HED">AGENCY:</HD> Environmental Protection Agency (EPA). <HD SOURCE="HED">ACTION:</HD> Final rule. <SUM> <HD SOURCE="HED">SUMMARY:</HD> The U.S. Environmental Protection Agency (EPA) is taking final action to partially approve and partially disapprove a submission by the State of California to revise its State Implementation Plan (SIP) relating to the control of emissions from non-gasoline combustion vehicles over 14,000 pounds. The EPA's partial approval will allow the submitted Heavy-Duty Inspection and Maintenance Regulation (“HD I/M Regulation”) to become federally enforceable as part of the California SIP with respect to vehicles registered within the State. The EPA is partially disapproving the submission to the extent that the HD I/M Regulation purports to apply to out-of-state vehicles as inconsistent with the Clean Air Act (CAA), because the State has not provided adequate assurances under CAA section 110(a)(2)(E)(i) that implementation of the SIP is not prohibited by Federal law. The partial disapproval will not trigger CAA section 179 sanctions because the submittal is not a required submission under CAA section 110(a)(2). </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> This rule is effective March 9, 2026. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> The EPA has established a docket for this action under Docket ID No. EPA-R09-OAR-2025-0061. All documents in the docket are listed on the <E T="03">https://www.regulations.gov</E> website. Although listed in the index, some information is not publicly available, <E T="03">e.g.,</E> Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, is not placed on the internet and will be publicly available only in hard copy form. Publicly available docket materials are available through <E T="03">https://www.regulations.gov,</E> or please contact the person identified in the <E T="02">FOR FURTHER INFORMATION CONTACT</E> section for additional availability information. If you need assistance in a language other than English or if you are a person with a disability who needs a reasonable accommodation at no cost to you, please contact the person identified in the <E T="02">FOR FURTHER INFORMATION CONTACT</E> section. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Doris Lo, EPA Region IX, 75 Hawthorne St., San Francisco, CA 94105; telephone number: (415) 972-3959; email address: <E T="03">lo.doris@epa.gov.</E> </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> Throughout this document, the use of “Agency,” “we,” “us,” or “our” refers to the EPA. We use multiple acronyms and terms in this preamble. While this list may not be exhaustive, to ease the reading of this preamble and for reference purposes, the EPA defines the following terms and acronyms here: <EXTRACT> <FP SOURCE="FP-1">ACT—Advanced Clean Trucks</FP> <FP SOURCE="FP-1">ATA—American Trucking Associations</FP> <FP SOURCE="FP-1">CAA—Clean Air Act</FP> <FP SOURCE="FP-1">CAELP—Center for Applied Environmental Law and Policy, Environmental Defense Fund, and Natural Resources Defense Council</FP> <FP SOURCE="FP-1">CARB—California Air Resources Board</FP> <FP SOURCE="FP-1">CBI—Confidential Business Information</FP> <FP SOURCE="FP-1">CCA—Coalition for Clean Air</FP> <FP SOURCE="FP-1">CCAEJ—Center for Community Action and Environmental Justice and Sierra Club</FP> <FP SOURCE="FP-1">CCR—California Code of Regulations</FP> <FP SOURCE="FP-1">CFR—Code of Federal Regulations</FP> <FP SOURCE="FP-1">CRA—Congressional Review Act</FP> <FP SOURCE="FP-1">CTA—California Trucking Association</FP> <FP SOURCE="FP-1">EPA—Environmental Protection Agency</FP> <FP SOURCE="FP-1">FIP—Federal Implementation Plan</FP> <FP SOURCE="FP-1">FSOR—Final Statement of Reasons</FP> <FP SOURCE="FP-1">GVWR—Gross Vehicle Weight Rating</FP> <FP SOURCE="FP-1">HD I/M—Heavy-Duty Inspection and Maintenance</FP> <FP SOURCE="FP-1">HDVIP—Heavy-Duty Vehicle Inspection Program</FP> <FP SOURCE="FP-1">ISOR—Initial Statement of Reasons</FP> <FP SOURCE="FP-1">MECA—Manufacturers of Emission Controls Association</FP> <FP SOURCE="FP-1">NTTAA—National Technology Transfer and Advancement Act</FP> <FP SOURCE="FP-1">NTTC—National Tank Truck Carriers</FP> <FP SOURCE="FP-1">OBD Standards—California Standards for Heavy-Duty Remote On-Board Diagnostic Devices</FP> <FP SOURCE="FP-1">OMB—Office of Management and Budget</FP> <FP SOURCE="FP-1">OOIDA—Owner-Operator Independent Drivers Association</FP> <FP SOURCE="FP-1">PRA—Paperwork Reduction Act</FP> <FP SOURCE="FP-1">PSIP—Periodic Smoke Inspection Program</FP> <FP SOURCE="FP-1">RFA—Regulatory Flexibility Act</FP> <FP SOURCE="FP-1">RFP—Reasonable Further Progress</FP> <FP SOURCE="FP-1">SCAQMD—South Coast Air Quality Management District</FP> <FP SOURCE="FP-1">SIP—State Implementation Plan</FP> <FP SOURCE="FP-1">TRALA—Truck Rental and Leasing Association</FP> <FP SOURCE="FP-1">UCS—Union of Concerned Scientists</FP> <FP SOURCE="FP-1">UMRA—Unfunded Mandates Reform Act</FP> <FP SOURCE="FP-1">U.S.C.—United States Code</FP> <FP SOURCE="FP-1">USMCA—United States-Mexico-Canada Agreement</FP> </EXTRACT> <HD SOURCE="HD1">Table of Contents</HD> <EXTRACT> <FP SOURCE="FP-2">I. Background</FP> <FP SOURCE="FP1-2">A. CAA Requirements</FP> <FP SOURCE="FP1-2">B. What regulations did the State submit?</FP> <FP SOURCE="FP1-2">C. What is the purpose of the submitted regulations?</FP> <FP SOURCE="FP1-2">D. What did the EPA propose?</FP> <FP SOURCE="FP-2">II. The EPA's Evaluation and Final Action</FP> <FP SOURCE="FP-2">III. Response to Public Comments and Discussion</FP> <FP SOURCE="FP1-2">A. Comments in Support of Partial Disapproval</FP> <FP SOURCE="FP1-2">B. Comments in Support of Full Approval</FP> <FP SOURCE="FP1-2">C. Other Comments</FP> <FP SOURCE="FP-2">IV. Incorporation by Reference</FP> <FP SOURCE="FP-2">V. Statutory and Executive Order Reviews</FP> </EXTRACT> <HD SOURCE="HD1">I. Background</HD> <HD SOURCE="HD2">A. CAA Requirements</HD> Under the CAA, the EPA establishes national ambient air quality standards (NAAQS) to protect public health and welfare. The EPA has established NAAQS for certain pervasive air pollutants including ozone, carbon monoxide, nitrogen dioxide, sulfur dioxide, lead, and particulate matter. Under CAA section 110(a)(1), States must submit plans that provide for the implementation, maintenance, and enforcement of the NAAQS within each State. Such plans are referred to as SIPs, and revisions to those plans are referred to as “SIP revisions.” CAA section 110(a)(2) sets forth the content requirements for SIPs. Among the various requirements, SIPs must include enforceable emissions limitations and other control measures, means, or techniques as may be necessary or appropriate to meet the applicable requirements of the CAA. <SU>1</SU> <FTREF/> SIP revisions may be submitted to address specific CAA requirements (such as the elements and demonstrations required within an attainment plan), or, as with the State submittal addressed in this action, may be provided to demonstrate emissions reductions to support attainment. <FTNT> <SU>1</SU>   <E T="03">See</E> CAA section 110(a)(2)(A). </FTNT> Upon receiving a SIP that meets the completeness criteria in CAA section 110(k)(1)(A), the EPA must determine whether the submission meets all applicable CAA requirements. <SU>2</SU> <FTREF/> The EPA must either approve, conditionally approve, approve in part and disapprove in part, or disapprove a complete State submission within twelve months. <SU>3</SU> <FTREF/> In addition to the limitations described above, CAA section 110(a)(2)(E) provides that a SIP must include “necessary assurances” that the State “is not prohibited by any Federal or State law from carrying out such implementation plan or portion thereof” and that the State or applicable State entity has adequate authority, personnel, and funding to carry out adequate implementation of the SIP. <FTNT> <SU>2</SU>   <E T="03">See</E> CAA section 110(k)(3). </FTNT> <FTNT> <SU>3</SU>   <E T="03">Id.;</E> CAA section 110(k)(4). </FTNT> Under California law, the California Air Resources Board (CARB) is the State agency responsible for adopting and submitting SIP revisions to the EPA for review. These include both local rules adopted by county and regional air districts (typically regulating stationary source emissions) and statewide regulations adopted by CARB and other State agencies. If approved into the SIP, submitted regulations become federally enforceable pursuant to CAA section 110(a)(2)(A). <HD SOURCE="HD2">B. What regulations did the State submit?</HD> CARB submitted the “Heavy-Duty Inspection and Maintenance Regulation”  <SU>4</SU> <FTREF/> (“HD I/M Regulation”) as a revision to the California SIP on December 14, 2022. <SU>5</SU> <FTREF/> Table 1 identifies the regulatory sections included in the HD I/M Regulation and addressed by this action with the dates that they were adopted by CARB and submitted to the EPA. <FTNT> <SU>4</SU>  The State of California more commonly refers to the HD I/M Regulation as the “Clean Truck Check.” <E T="03">See, e.g.,</E> CARB, Clean Truck Check (HD I/M), <E T="03">https://ww2.arb.ca.gov/our-work/programs/CTC</E> (last visited January 26, 2026). </FTNT> <FTNT> <SU>5</SU>  Letter (with enclosures) dated December 7, 2022, from Steven S. Cliff, Ph.D., Executive Officer, CARB, to Martha Guzman, Regional Administrator, EPA Region IX (submitted electronically December 14, 2022 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 213k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━