Operating a refrigerated fleet in California comes with strict compliance requirements. The California Air Resources Board (CARB) enforces one of the nation’s most rigorous transport refrigeration unit (TRU) regulatory programs, and understanding these rules is important for fleet operators, brokers, forwarders, shippers and receivers. Non-compliance can result in operational restrictions, fines and exclusion from California’s freight networks.
This article explains CARB TRU compliance, its impact on your operations and how fleets can proactively reduce TRU emissions while staying compliant.
Key Takeaways
- CARB TRU compliance is mandatory for all fleets and subcontractors operating TRUs in California.
- Regulations cover fleet registration, reporting, labeling, refrigerant standards, particulate emissions and phased transition to zero-emission truck TRUs.
- A law signed on September 17, 2025, ruled that regulated entities must pay TRU ATCM fees, register all TRUs at their facilities and submit TRU operating reports.
- New TRUs (model year 2023+) must use refrigerants with GWP <2,200 and meet stricter particulate emission standards.
- All truck-mounted TRUs must transition to zero-emission technology by December 31, 2029.
- Non-compliance may lead to fines, operational restrictions, and exclusion from CARB’s “100 Percent-Compliant Carrier” list.
- Retrofitting older TRUs (e.g., via active diesel particulate filters (DPFs)) offers a pathway to meet emissions standards without full unit replacement.
CARB TRU compliance, in plain English
CARB TRU compliance ensures that all transport refrigeration units meet California emissions and refrigerant standards. The 2022 TRU ATCM amendments include:
- Registration in ARBER for all TRUs operating in California
- Compliance labels, now required for all in-use TRUs
- PM emission standards for in-use and new units
- Lower-GWP refrigerants for in-use and newly manufactured units
- Phased zero-emission requirements for truck-mounted TRUs
These requirements apply to both your own fleet and any subcontracted carriers operating in California. Non-compliant TRUs are not eligible for CARB’s 100 Percent-Compliant Carrier List, meaning brokers, shippers and receivers cannot legally hire them for California freight.
What’s covered
- TRU types: truck-mounted, trailer-mounted, railcar-mounted, containerized and generator-set units
- Compliance focus: PM performance, refrigerant standards, registration, labeling and zero-emission transition
- Operational impact: Non-compliance can restrict facility access and disrupt freight operations
CARB reefer regulations
Understanding CARB reefer regulations is essential for maintaining legal operations. Fleet operators must ensure their units, and those of subcontractors, comply with all current requirements.
Requirements for fleets operating TRUs in CA
- Fleet operators are responsible for both their own units and those of subcontractors
- Drivers must carry contact information for the shipper, receiver and hiring business
- Drivers must provide documentation on request, including:
- Driver’s license
- Vehicle registration
- Bill of lading or freight bill with origin and destination
- Violations may result in citations
How to check compliance
CARB provides tools to verify TRU compliance:
- ARB Public TRU Search – Check individual TRUs or generator sets
- TRU Compliance Check Resources – Guidance for carriers, brokers, forwarders, shippers and receivers
Staying current with CARB regulations
The 2022 TRU ATCM amendments are in effect, and additional compliance updates took effect in 2025. As of September 17, 2025, CARB now imposes fees on entities regulated under the TRU ATCM, and facility owners must register with CARB, pay registration fees and report all TRUs operating at their facility.
New TRUs must use refrigerants with a Global Warming Potential (GWP) less than 2,200, and units manufactured in model year 2023 or later must meet stricter particulate emission standards. Additionally, all truck-mounted TRUs must transition to zero-emission technology by December 31, 2029.
Fleet operators should monitor CARB updates closely to remain compliant, avoid enforcement actions and maintain eligibility for California freight operations. Non-compliance can lead to citations, operational restrictions and exclusion from the CARB “100 Percent-Compliant Carrier” list.
Partnering with providers who offer CARB-verified emissions control solutions can reduce the administrative burden, simplify compliance and ensure fleets remain operational under evolving regulations.
How to decrease TRU emissions now
Replacing entire fleets can be costly, but you can significantly help in decreasing TRU emissions from existing units without full replacement. One effective solution is retrofitting TRUs with active diesel particulate filters (DPFs) that regenerate at any load.
Benefits of active DPFs for your TRU fleet:
- Reduce diesel particulate emissions to meet CARB standards.
- Avoid the operational disruptions and costs of replacing older units.
- Ensure your fleet remains eligible for CARB’s 100 Percent-Compliant Carrier List.
Rypos offers active DPFs for TRUs, helping refrigerated fleets stay compliant while reducing emissions by up to 95%. For more information, contact Rypos or visit rypos.com.