California Air Resources Board

California Air Resources Board staff are developing approval criteria for zero‑emission transport refrigeration units (ZE TRUs). The goal is to create a clear, consistent framework for evaluating these technologies, ensuring transparency for owners and operators, and providing confidence that ZE TRUs meet basic expectations for design, performance, reliability, durability, warranty, and other key factors.​ These approval criteria are intended to support future TRU emission reduction strategies and help determine eligibility for funding programs.

We’re looking for feedback on our draft approval criteria. Send your feedback to zeapprovals@arb.ca.gov by August 28, 2026.