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Mobile Source Regulations

Yorke Engineering has assisted over 100 facilities with navigating the statewide and regional mobile source regulations that impact their operations. Our services include determining which mobile source regulations apply to the fleet and assisting with reporting in the Diesel Off-Road Online Reporting System (DOORS); Truck Regulations, Upload, and Compliance Reporting System (TRUCRS); Advanced Clean Truck (ACT) Large Entity Reporting (LER) Portal; and the South Coast Air Quality Management District’s (SCAQMD’s) Program Online Portal (POP).

Advanced Clean Fleets (ACF)

CARB is developing the next phase of regulations to transition fuel-based on-road vehicles to Zero Emission technologies, such as battery-electric and hydrogen fuel-cell vehicles. CARB’s Advanced Clean Truck (ACT) regulation requires companies selling trucks in California to meet certain Zero Emission Vehicle (ZEV) or Near-Zero Emission Vehicle (NZEV) sales goals starting in 2024. In addition, “large entities” with operations in California were required to provide a one-time report in 2021 on the trucks that they own or direct in California.

Yorke Engineering is closely tracking the ongoing development of the Advanced Clean Fleet (ACF) regulations, including:

  • Advanced Clean Fleet drayage trucks;
  • Advanced Clean Fleet public fleets; and
  • Advanced Clean Fleet high-priority fleets.

To learn more about this suite of regulations, visit CARB’s website for the Advanced Clean Fleet program.

On-Road Heavy-Duty Diesel Vehicles (HDDVs)

Diesel vehicles with a gross vehicle weight rating (GVWR) greater than 14,000 pounds have distinct 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 1,000 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;
  • Compliance support for the CARB Fleet Rule for Public Agencies and Utilities (PAU);
  • TRUCRS reporting assistance to demonstrate compliance with the flexibility options of the Truck and Bus Regulation, including low-use, low-mileage work truck, phase-in, small fleet, and agricultural provisions and exemptions;
  • Managing smoke test requirements, including the transition from the Periodic Smoke Inspection Program (PSIP) to the Heavy-Duty Inspection and Maintenance (HD I&M) Program requirements; and
  • Assistance with additional on-road regulatory requirements (such as new ACF rules).

Off-Road Diesel

In total, our clients have well over 250,000 horsepower (hp) in off-road diesel equipment. Some facilities have only a handful of equipment, and others have more than 50 pieces of equipment. No matter the fleet size, Yorke can help bridge the gap between California Air Resources Board (CARB) compliance requirements and a facility’s equipment maintenance management strategies. A few of the typical tasks commonly performed are shown below as examples:

  • Fleet average and Best Available Control Technology (BACT) compliance calculations;
  • Long-term compliance planning, including beyond 2023;
  • DOORS reporting assistance;
  • Low-use tracking;
  • Flex engine reporting;
  • Agricultural provisions and exemptions;
  • Cargo handling equipment compliance assistance for operations at a Port or Intermodal Railyard; and
  • Preparing for the next phase of regulatory requirements due to upcoming Amendments to existing regulations or proposed new regulations.
    • Note this regulation is in the process of being amended with likely passage in 2022/2023. There may be new requirements around renewable diesel, mandatory phase out of older vehicles, and more. We are tracking this development and can provide more details as requested.

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;
  • Agricultural provisions and exemptions; and
  • Preparing for the next phase of Zero Emission Forklift Fleet regulatory requirements.


    Since 2018 and the advent of AB 617, the push for funding for cleaner mobile sources has increased. Yorke can help navigate funding programs to find potential opportunities that suit each facility’s operational needs, and can assist with the application process. Some of the most common funding programs include:

    • Carl Moyer Program Funding for Vehicle Replacement or Engine Repower (statewide funding with project types and timelines that vary by district);
    • Hybrid and Zero-Emission Truck and Bus Voucher Incentive Project (HVIP);
    • California Clean Off Road Equipment (CORE) Voucher Incentive Program;
    • Funding Agricultural Replacement Measures for Emission Reductions (FARMER) statewide program;
    • Surplus Off-Road Opt-In for NOx (SOON) Funding Assistance for Fleets Operating in the South Coast Air Basin (SCAB);
    • Proposition 1B Goods Movement; and
    • Vokswagen (VW) Mitigation Funds (available statewide in a variety of categories, such as zero emission vehicle replacement, zero emission infrastructure, zero emission forklifts, etc.)

    Main Office:

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