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  2. Verified Technologies for SmartWay and Clean Diesel
  3. SmartWay Technology
  4. For Trucks & School Buses

Refrigerated Trailers and Transport Refrigeration Units (TRUs)

Transport Refrigeration Unit Calculator (TRU)

Refrigerated trucks and trailers (or reefers) are an integral part of transporting freight that requires climate-controlled conditions. Almost all perishable foods and medicines are delivered in trucks or tractor trailers equipped with transport refrigeration units (TRUs), which are most often powered by small diesel engines. While modern diesel engines emit less emissions compared to older engines, there are new TRU designs and systems with electric plug-in capabilities that can significantly reduce emissions, particularly while parked at distribution centers, warehouses, and grocery stores and centers. Additional resources describing these systems and opportunities will be coming soon. In the meantime, please explore the EPA’s new TRU Emissions Calculator and existing guidance from the DERA program.

Additional Resource

  • DERA - Diesel Emissions Reduction Act Program
  • 2020 Diesel Emissions Reduction Act (DERA) National Grants Transport Refrigeration Unit (TRU) Factsheet (pdf) (December 2019, EPA-420-F-19-074)
  • Shore Power Technology Assessment at U.S. Ports

TRU Emissions Calculator

The TRU Emissions Calculator can be used to estimate the potential emissions reduction from operating transport refrigeration units on grid power, compared to traditional diesel power.

  • Use the NEW calculator
    • TRU Emissions Calculator Final Version 2023 (xlsx) (3.07 MB, March 2023)
    • The March 2023 version includes:
      • A User Guide tab and References tab within the calculator.
      • General and Detailed data input modes.
      • The Latest emission factors for small diesel engines used in TRUs.
      • TRU emissions are estimated using emission factors from EPA’s Emissions & Generation Resource Integrated Database.
      • (eGRID) 2020 data and diesel TRU emissions are estimated using outputs from EPA’s MOVES3 emissions model.
  • For Reference Only
    • TRU Emissions Calculator Version 2022 (xlsx) (1.21 MB, October 2022)
    • The October 2022 version includes:
      • A User Guide tab and References tab within the calculator.
      • The Latest emission factors for small diesel engines used in TRUs.
      • eGRID 2018 electricity power plant emissions factors, including emissions factors for particulate matter (PM).

If you have questions about EPA Technology Assessments, please email: The Tech Center (Tech_Center@epa.gov)

Verified Technologies for SmartWay and Clean Diesel

  • Clean Diesel Technology
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  • SmartWay Technology
    • For Trucks & School Buses
      • Designated Tractors
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      • Refrigerated Trailers and TRU Calculator
      • Aerodynamic Devices
      • Idling Reduction
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Contact Us about Verified Technologies for SmartWay and Clean Diesel
Contact Us to ask a question, provide feedback, or report a problem.
Last updated on April 23, 2025
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