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CARB Mobile Source Regulations

Yorke Engineering, LLC has assisted numerous facilities with determining which mobile source regulations apply to their fleet and the appropriate reporting in the Diesel Off-Road Online Reporting System (DOORS) and Truck Regulations, Upload, and Compliance Reporting System (TRUCRS).

Off-Road Diesel

In total, our clients have over 100,000 horsepower (HP) in off-road diesel equipment. Some facilities have only a handful of equipment, and others have over 50 pieces of equipment. No matter the fleet size, Yorke can help bridge the gap between California Air Resources Board (CARB) compliance requirements and your facility’s equipment maintenance management strategies. A few of the typical tasks commonly performed are shown below as examples.

  • Long-Term Compliance Planning;
  • Fleet Average and Best Available Control Technology (BACT) Compliance Calculations;
  • DOORS Reporting Assistance;
  • Low-Use Tracking;
  • Flex Engine Reporting;
  • Agricultural Provisions and Exemptions; and
  • Cargo Handling Equipment Compliance Assistance.

Large Spark-Ignition (LSI)

Yorke has assessed over 500 pieces of LSI equipment and found exemptions for about 15% of them. Yorke reported well over 350 LSI forklifts into DOORS for the initial reporting requirement that began on June 30, 2017. A few of the typical tasks commonly performed are shown below as examples.

  • Fleet Assessments;
  • Fleet Average Calculations;
  • DOORS Reporting Assistance;
  • Low-Use Tracking; and
  • Agricultural Provisions and Exemptions.

On-Road Heavy-Duty Diesel Vehicles (HDDVs)

Diesel vehicles with a gross vehicle weight rating (GVWR) greater than 14,000 pounds have fleet requirements in California. Yorke has assisted fleets of varying sizes, including everything from small fleets with fewer than three vehicles to large fleets with over 100 vehicles. A few of the typical tasks commonly performed are shown below as examples.

  • Compliance Assessments and Long-Term Compliance Planning for Companies Subject to the Truck and Bus Regulation and the Fleet Rule for Public Agencies and Utilities (PAU);
  • TRUCRS Reporting Assistance;
  • Compliance Options, Including Low-Use, Low-Mileage Work Truck, Phase-In, Small Fleet, and Agricultural Provisions and Exemptions; and
  • Assistance with Proposition 1B: Goods Movement Emission Reduction Program.


Since 2018 and the advent of AB 617, there has been a push for funding for cleaner mobile sources. Yorke can inform you about funding from the following programs.

  • Carl Moyer Program Funding for Equipment Replacement or Engine Rebuilding (funding requirements may vary district by district, but funding is available statewide);
  • Funding Agricultural Replacement Measures for Emission Reductions (FARMER) Statewide Program; or
  • Surplus Off-Road Opt-In for NOx (SOON) Funding Assistance for Fleets Operating in the South Coast Air Basin (SCAB).

Main Office:

31726 Rancho Viejo Rd. Suite 218
San Juan Capistrano, CA 92675


Phone: +1 (949) 248-8490
Email: info@YorkeEngr.com