California’s TRU Regulations Are Transforming Fleet Operations: Here’s What Every Fleet Owner Must Know About 2024 Compliance Changes
California’s transportation refrigeration unit (TRU) regulations have undergone significant changes that are reshaping how fleet owners approach compliance in 2024. With zero-emission truck TRU requirements beginning December 31, 2023, requiring TRU owners to turnover at least 15 percent of their truck TRU fleet to zero-emission technology each year, with all truck TRUs operating in California required to be zero-emission by December 31, 2029, the stakes have never been higher for fleet operators.
Understanding the Current Regulatory Landscape
The California Air Resources Board (CARB) has implemented sweeping changes to address what it calls toxic and harmful emissions from diesel-powered TRUs. These regulations apply to all diesel TRUs on straight truck or van chassis operating in the state, even if they are domiciled elsewhere.
The phase-in requirements vary significantly based on fleet size. Fleets with four, five or six trucks must have at least one vehicle that is a ZEV, while for fleets with seven or more trucks, 15% must be ZEVs. In 2024, requirements ramp up to one ZEV for fleets with two, three or four trailers, two ZEVs for five- or six-truck fleets, and 30% ZEVs for fleets with seven or more trucks.
Key Compliance Requirements Fleet Owners Must Address
Beyond the zero-emission transition, several critical compliance elements demand immediate attention:
- Expanded TRU reporting – Beginning December 31, 2023, TRU owners shall report all TRUs (including out-of-state based) that operate in California to CARB
- TRU operating fees and compliance labels: Fleet owners must pay TRU operating fees and affix CARB compliance labels to their TRUs every three years
- As of Jan. 1, 2024, TRU manufacturers can no longer pull any power whatsoever off of an internal combustion diesel engine in California
Recent Regulatory Relief and What It Means
Fleet owners received some relief in early 2025 when U.S. EPA waived federal preemption for all but the zero-emission TRU requirements. This means that manufacturers of transport refrigeration units may manufacture, for sale or use in California, new diesel-fueled truck TRUs that are otherwise compliant with the TRU ATCM, and California dealers may sell newly-manufactured diesel-fueled truck TRUs that are otherwise compliant.
However, this doesn’t eliminate compliance obligations entirely. Extensions can temporarily delay compliance, but these obligations compound (i.e., 15% in 2023, 30% in 2024, 45% in 2025, etc.) and will require fleets to make large-scale deployments when the technology is available and/or validated.
Practical Challenges Fleet Owners Face
The transition to zero-emission TRUs presents significant operational challenges. Industry feedback highlights concerns about vast complications and unreliability, with technology needing to improve before a regulation like this can go into effect. Fleet operators also face the risk of not keeping perishables within the required temperature range, which could happen if charging were not available.
Compliance Extensions and Support Options
Recognizing these challenges, CARB has expanded compliance extension options. Compliance extensions due to private financing, equipment manufacture delays, or installer delays may be granted for a maximum of six months (previously four months). TRU owners or operators may apply for compliance extensions based on the unavailability of compliance technology, as well as zero-emission infrastructure, manufacturer, installer, or financing delays.
The Path Forward for Fleet Compliance
For fleet owners navigating these complex requirements, working with experienced automotive service providers becomes crucial. Professional CARB Compliant Santa Monica, CA services can help ensure your fleet meets all necessary emissions standards while minimizing operational disruptions.
The regulatory landscape continues evolving, with TRU Part 2 proposals requiring fleets to replace 5% of non-zero emissions Non-truck TRUs with zero emission units each year for 2028 and 2029, with turnover requirements increasing to 10% for 2030 and 2031, 15% for 2032 and 2033, and 20% for 2034 and 2035.
Taking Action Now
Fleet owners should immediately assess their current TRU inventory and develop transition strategies. Fleets making purchases should evaluate whether it makes sense to buy a new diesel reefer unit, as in most cases, it would make more sense to go ahead and buy a zero-emissions unit.
The window for compliance planning continues narrowing, making professional guidance essential. Understanding these regulations and implementing appropriate compliance strategies will determine whether your fleet thrives or faces costly penalties in California’s evolving regulatory environment.
As we move through 2024, staying informed about regulatory updates and working with qualified automotive professionals becomes not just advisable—it’s essential for maintaining operational continuity and avoiding significant financial penalties.