New Transport Refrigeration Unit Regulation (In development)

This page last reviewed December 18, 2018

Existing TRU Regulation can be found here: TRU Website



California needs to reduce residual public health risk from Transport Refrigeration Units (TRU) near distribution centers and other facilities where TRUs and TRU generator sets congregate; as well as achieve emission reductions while in transit, especially near the most impacted communities.  Improving freight efficiency and transitioning to zero or near-zero emission technologies will help reduce toxic air contaminant emissions, criteria pollutant emissions, and GHG emissions.

TRUs are currently defined as refrigeration systems that are powered by internal combustion engines (inside the unit housing). They control the environment of temperature-sensitive products that are transported in refrigerated trucks, trailers, railcars and shipping containers.  They may be capable of cooling or heating.  TRUs are used to transport and store many products, including, but not limited to food, pharmaceuticals, plants, medicines, blood, chemicals, photographic film, art work, and explosives.

Some companies use TRUs for extended cold storage during the four- to six-week period before major holidays and events.  Distribution centers and grocery stores are known to run out of cold storage space in their buildings, so they store overflow goods in TRU-equipped trucks and trailers outside the grocery stores and distribution centers.  Distribution centers and other cold storage facilities also attract large volumes of TRUs that contribute to higher localized health risk in nearby communities.  The new regulation is developing concepts to reduce emissions from facilities with TRU activity by transitioning to zero-emission operation where practical.  

Status (as of December 18, 2018):

Previous Posts:

Posted July 21, 2017
Public Workshop Series

Workshop Series #2:
     Date:   Wednesday, August 16, 2017
     Time:   9:30 a.m. - 11:30 a.m.

     Place:  California Environmental Protection Agency Headquarters
                Sierra Hearing Room
                1001 I Street, 2nd Floor
                Sacramento, California  95814

The Sacramento workshop will also be webcast on the day of the workshop only.
      The webcast connection is at:

     Date:    Friday, August 18, 2017
     Time:   1:00 p.m. - 3:00 p.m.

     Place:  Riverside County Administration Center
                 4080 Lemon Street, 1st Floor
                 Riverside, California  92501

     Public Notice (Spanish version)
     Presentation (with Emission Inventory slides) (Spanish version - does not include Emission Inventory slides)

Posted April 25, 2017

ARB has published a Request for Proposal (RFP) No. 16TTD008 titled "Data Collection and Business Case Study for eTRUs."  This RFP can be found at the California State Contracts Register at:  Any questions/comments should be emailed to or by phone to (916) 322-8452.

Posted March 1, 2017

Proposition 1B Funding

ARB Executive Order G-17-004 made changes to the Proposition 1B Final 2015 Guidelines for Implementation (Program Guidelines), which may benefit refrigerated fleets and grocery store chains that use TRUs for cold storage behind grocery stores.  Click here for further description of these changes.

Posted September 7, 2016

Clean TRU Technology Webinar

ARB hosted a "Clean TRU Technology Webinar" on August 31, 2016, where staff and clean technology manufacturers discussed clean TRU technology options and the availability of Proposition 1B funding.  See links to the agenda and slides handout, below.  A video recording of the webinar is available here.
     Slides Handout

Posted March 8, 2016

Public workshop Series 

California Air Resources Board (CARB) staff conducted a series of public workshops to discuss concepts to reduce air pollution emissions from TRUs.

Workshop #1:  
     Date:   April 13, 2016
     Time:  10:00 a.m. to 12:00 p.m.
     Place:  Sierra Hearing Room (2nd floor)
                1001 I Street, Sacramento, California 95814

Public notice
                This workshop will also be webcast.  The webcast connection is at:

Posted October 12, 2015

Proposition 1B funds are currently available for the replacement of existing diesel TRUs with zero-emission TRs, as well as the purchase and installation of electric and/or cryogenic infrastructure.  Such infrastructure could be used for zero-emission units, or hybrid electric TRUs and TRU equipped with electric standby. Solicitations open periodicaly at certain California air districts, which are listed at ARB's Goods Movement Website.

Posted August 27, 2015

Zero Emission Transport Refrigerator Technologies List.  
This list includes a brief technology description, manufacturer's company name, brand or model, website address, and contact information.  A zero emission transport refrigerator must not be powered by an internal combustion engine in any way (i.e. zero tailpipe emissions).  Electric power for refrigeration system compressor, fans, and controls may come from on-board batteries, provided they are not re-charged by an alternator or generator that is driven by the vehicle engine or powertrain, trailer wheels, trailer axle/differential, or any other contrivance that adds to the vehicle drag and/or engine load.  Examples of zero emission TRs include, but are not limited to, TRs with refrigeration system and/or fans that are powered by batteries when on-road, and use battery chargers that are plugged into the electric power grid while stationary or connected to on-board solar panels.

Posted July 31, 2015

The California Air Resources Board (ARB/Board) announces the release of the draft document “Technology Assessment: Transport Refrigerators." The draft technology assessment can be viewed and downloaded from the ARB’s technology and fuels assessment webpage at:
If you have questions regarding the draft technology assessment, please contact Mr. Rodney Hill, Staff Air Pollution Specialist, at 916-327-5636, or email to 

Sign up for the TRU email list to get news and notices related to the TR4 ATCM and incentive funding for zero-emission TRs and related infrastrucutre.