CARB Approved Amendments to the Off-road Diesel Regulation

Amendments to CARB’s Off-road Diesel Regulation

As mentioned in a previous issue, the California Air Resources Board approved amendments to the Off-road Diesel Regulation. The amendments included new requirements which start on January 1, 2024.

These requirements are:

• Ban on Adding Vehicles with Tier 3 Engines – All fleets are banned from adding vehicles with Tier 3 engines on January 1, 2024.
• Ban on Adding Vehicles with Tier 4 Interim Engines – Large (>5000 total hp) and Medium fleets (hp between 2,500 and 5,000) are banned form adding vehicles with Tier 4 Interim engines on January 1, 2024. To be added to these fleets the vehicle’s engine must be Tier 4 Final.
• Renewable Diesel Mandate – Beginning January 1, 2024, fleets are required to use only renewable diesel in their off-road fleet or submit to arduous recordkeeping requirements showing the fuel is not available. The fleet’s responsible official is required to sign an affirmation that the fleet complies with this requirement annually.
• Tier 0 Vehicle Phase out for Large Fleets – Large fleets are banned from operating vehicles with Tier 0 engines unless those vehicles are reported as low use and meeting the hour limitations of the low use provision. 
• Prime Contractor Requirements - Prime contractors are required to hire fleets complying with the off-road diesel regulation and keep records that they have done so. Non-compliant fleets are reported to CARB.
• Low Use – Year by Year Low Use provision sunsets and becomes a permanent Low Use Provision with a 3-year 200-hour rolling average limit.

If you have any questions about what this regulation may mean for your fleet please feel free to reach out to Associates Environmental’s Drew Delaney, ddelaney@associatesenvironmental.com (949) 322-3739.