California Air Resources Board

Amendments to the In-Use Off-Road Diesel-Fueled Fleets Regulation

Introduction

The recent amendments to the In-Use Off-Road Diesel-Fueled Fleets Regulation (Off-Road Regulation or regulation), approved by the California Air Resources Board (CARB) in 2022 (2022 amendments), incorporate new low-use requirements. This fact sheet reviews key elements of the regulation’s low-use requirements and highlights the changes in the 2022 amendments, including:

• The permanent low-use exemption is expanded to allow a three-year rolling average;
• Required reporting for the permanent low-use exemption is expanded; and
• The year-by-year low-use exemption is discontinued on January 1, 2024.

Background

Recognizing that equipment that is used less has less of an emissions impact, CARB included low-use provisions in the regulation in order to exempt equipment that is rarely used from potentially costly retrofit or replacement requirements. Year-by-year low-use means a vehicle that operated in California less than 200 hours during the previous calendar year, but that could operate more than 200 hours in the future. CARB discontinued the year-by-year low-use exemption because it is incompatible with the tier phase-out requirements approved in the 2022 amendments. Originally the year-by-year exemption allowed vehicles to move in and out of low-use status from one year to the next, however, this could cause a vehicle coming out of low-use status to immediately become noncompliant with the tier phase-out requirements.

The permanent low-use exemption provides fleet owners two key benefits:

1. Permanent low-use vehicles do not have to be removed from the fleet as long as their usage stays below the low-usage thresholds, with one exception for Tier 0 permanent low-use vehicles which must be retired before January 1, 2036.
2. Permanent low-use vehicles are not counted towards a fleet’s total horsepower.

The permanent low-use exemption historically has only provided an exemption based on one year of usage data. The exemption was expanded in the 2022 amendments to also allow a three-year rolling average, offering additional flexibility to fleets. Therefore, there are two ways to qualify for a permanent low-use designation, using usage data from a single year or using data from three-years that rolls forward every year. Once a vehicle is designated permanent low-use, it must operate at low-use levels for the remainder of its life.

Requirements

Amendments to the low-use requirements take effect January 1, 2024. To qualify for the permanent low-use exemption, a vehicle must:

• Operate on average 200 or fewer hours per year or less than 600 hours over a three-year period.
• For two-engine vehicles, both engines must separately meet the permanent
  low-use requirements to qualify.
• Permanent low-use vehicles must have a non-resettable hour meter installed.
• Vehicles designated as permanent low-use are in violation of the regulation if operated more than 200 hours per year. To increase the use to 200 hours or more per year, the vehicle must meet the current adding vehicles requirements in section 2449(d)(6).

Reporting [Section 2449(g)(2)(C)]

• Low-use vehicles are required to report their hour meter reading for their low-use vehicles every year as follows:
  • Engine hour meter readings are due to CARB by March 1 each year.
  • Usage data must cover the calendar year between January 1 and December 31 of that year.

  • The engine hour meter reading must be recorded within 30 days of January 1.

• For the one-year calculation, the usage report is for a one-year period. For example, in 2025, the usage hours between January 1, 2024, and December 31, 2024, is reported. The meter reading must be taken within 30 days of January 1, 2025, and reported to CARB by March 1, 2025. Usage has to be less than 200 hours in one year.

• For the three-year rolling average, the low-use designation is based on three years of reported usage data. As with the one-year usage exemption, usage data is reported for a calendar year, the data is collected within 30 days of January 1, and it must be reported to CARB by March 1. However, in this case, the sum of three years of usage data cannot exceed 600 hours.

• The 2022 amendments expanded the reporting requirements to include a date-stamped photograph of the engine hour meter reading. Fleets must maintain the photograph in accordance with the recordkeeping requirements of the Current Regulation (Section 2449(h)). The photo does not need to be submitted to CARB until requested.
  
  In the case where the fleet does not have access to a camera or if security protocols related to military operations prevent the use of a camera, they can create a written log of their hour meter readings that must be signed and dated. The log must include the vehicle’s equipment identification number, commonly referred to as the EIN, hour meter reading, a signature and date from the day that the hour meter reading was gathered for reporting, and must be maintained in accordance with the recordkeeping requirements (Section 2449(h)).

• If a low-use hour meter is replaced, changed, or altered in any way, CARB must be notified during the subsequent reporting period. Reported information must include the replacement date and the hour meter reading on the old meter.

Operated Outside of California

• Low-use vehicles that operate both inside and outside of California must submit a log that includes the date and hour meter reading of each time the vehicle enters or exits California (Section 2449(g)(2)(C)(3)(a)).

Labeling

• Low-use vehicles continue to be subject to labeling requirements (Section 2449(f))

Phase-Out of Tier 0 Low-Use [Section 2449.1(c)(4)]

• Permanent low-use vehicles with a Tier 0 engine must be removed from operation by January 1, 2036.

Year-by-Year Low-Use Exemption Discontinued [Section 2449(c)(73)(E)]

Beginning January 1, 2024, the year-by-year low-use exemption is discontinued. In turn, CARB added the three-year rolling average allowance into the permanent low-use vehicle exemption to ensure flexibility.

While this document is intended to assist fleets with their compliance efforts, it does not alter or modify the terms of any CARB regulation, nor does it constitute legal advice. It is the sole responsibility of fleets to ensure compliance with the Regulation for In-Use Off-Road Diesel‑Fueled Fleets.