California Air Resources Board

​ Overview

The purpose of this guidance is to provide vehicle owners with updated information on the expected start date of Clean Truck Check periodic compliance testing in 2024 and projected compliance deadlines for vehicles subject to semiannual (twice per year) testing. It augments previous guidance released in late June 2023 on CARB’s plans to implement a three-month open reporting season projected to run from October 1, 2023, to December 31, 2023. To access the previous guidance, please see: June 2023 Guidance to Vehicle Owners on Upcoming Requirements | California Air Resources Board.

Key highlights from this guidance are:

• CARB staff projects that periodic testing requirements will start for vehicles on their first compliance deadline on or after July 1, 2024. Tables I and II present projected 2024 compliance deadlines.
  • A passing compliance test will be required to be submitted to CARB within the 90 days before a vehicle’s compliance deadline.
• 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).

Vehicles Affected by this Guidance

Nearly all diesel and alternative fuel heavy-duty trucks, buses, and other vehicles with a gross vehicle weight rating over 14,000 pounds that operate in California are subject to semiannual testing and the projected compliance deadlines presented in Table I and Table II below. Affected vehicles include hybrid trucks and buses, commercial vehicles, privately-owned vehicles, government vehicles, and vehicles registered outside of California. For information on vehicles that are exempt from Clean Truck Check, please refer to the Fact Sheet: Heavy-Duty Inspection and Maintenance Program: Background and Requirements.

California registered motorhomes and heavy-duty vehicles used exclusively in agricultural operations (California registered and non-California registered) are required to undergo periodic compliance testing annually, rather than semiannually. Annual 2024 compliance schedules for these vehicles are presented in ”Guidance to Vehicle Owners on 2024 Periodic Testing Requirements for Vehicles Subject to Annual Testing: California Registered Motorhomes and Agricultural Vehicles.”

2024 Periodic Testing Requirements

CARB staff projects that periodic testing will start for vehicles on their first compliance deadline on or after July 1, 2024. This will provide vehicle owners with added time to determine which compliance testing option best meets their needs. For the 2024 calendar year only, vehicles subject to semiannual compliance testing will be required to test only once, as described below. 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.

A. California Registered Vehicles

Compliance deadlines for California registered vehicles are based on their DMV registration expiration dates. In general, a vehicle required to test semiannually will have two compliance deadlines each year: 1) on its DMV registration expiration day; and 2) six months after the DMV registration expiration date. To identify when your vehicle’s one 2024 periodic compliance test will be required, refer to Table I below.

Table I: 2024 Projected Periodic Compliance Testing Deadlines for California Registered Vehicles

For a California registered vehicle, its compliance deadline is based on the numerical day of its DMV expiration. Examples of compliance deadlines using Table I include:

• A vehicle with a DMV registration expiration on January 31, 2024, will have a 2024 compliance deadline on July 31.
• A vehicle with a DMV registration expiration on July 31, 2024, also will have a 2024 compliance deadline on July 31.
• A vehicle with a DMV registration expiration on May 31, 2024, will have a 2024 compliance deadline on November 30 (the last day of November).

Starting in 2025, California registered vehicles will be subject to both semiannual compliance deadlines. In all cases, a passing compliance test must be submitted to CARB within the 90 days before a compliance deadline. This period is referred to as the 90-day submission window. Figure I below illustrates the compliance deadlines and
90-day submission windows in 2024 and 2025 for a vehicle with a May 31st DMV registration expiration.

Figure I: Projected Periodic Testing Dates for a Vehicle with a May 31st DMV Registration Expiration Date

B. Non-California Registered Vehicles and DMV Exempt Plated Vehicles

Non-California registered vehicles include vehicles registered in other states and countries, as well as federal vehicles not registered in any DMV jurisdiction. DMV exempt plated vehicles include California local and state government vehicles exempt from DMV re-registration requirements.

These vehicles will also have two compliance deadlines each year, however, the determination of these dates is based on the last number of the vehicle’s vehicle identification number (VIN). For further details, refer to the Fact Sheet: Heavy-Duty Inspection and Maintenance Regulation: Periodic Testing Requirements. As mentioned above, each vehicle will be subject to one periodic compliance deadline in 2024. To identify when your non-California registered/exempt plated vehicle’s one 2024 periodic compliance test is required, refer to Table II below. Starting in 2025, these vehicles will have reoccurring compliance deadlines every six months.

Table II: Projected 2024 Periodic Compliance Testing Deadlines for Non-California Registered and DMV Exempt Plated Vehicles

In the VIN-based compliance schedule, a vehicle’s periodic compliance testing deadline falls on last day of the compliance deadline month shown in Table II.  Examples of compliance deadlines using Table II include:

• A vehicle with “7” as the last number in its VIN would have a compliance deadline on November 30 in 2024.
• A vehicle with “1” as the last number in its VIN would also will have a 2024 compliance deadline on November 30 in 2024.
• A vehicle with “0” as the last number in its VIN would have a compliance deadline on October 31 in 2024.

Figure II below illustrates the compliance deadlines and 90-day submission windows in 2024 and 2025 for a vehicle with a “0” as the last number in its VIN. In 2024, this vehicle will be subject to a compliance deadline of October 31. Moving forward, this vehicle will have reoccurring compliance deadlines every six months on April 30 and then again on October 31 in 2025 and beyond.

Figure II: Projected Periodic Testing Dates for a Vehicle with a “0” as Last Number in its VIN