Zero-Emission Truck Adoption at California Warehouses: Who Is Adopting, Who Is Left Behind, and Why?

The South Coast Air Quality Management District's (AQMD) Warehouse Actions and Investments to Reduce Emissions (WAIRE) Program is the nation's first indirect source rule (ISR) for warehouses. It requires nearly 4,000 warehouse operators across Southern California to annually take actions that reduce emissions, such as acquiring or using a zero-emission (ZE) truck. However, roughly 60% of regulated operators are estimated not to own the truck fleets visiting their facilities, creating a complex regulatory intermediation challenge: operators must influence emissions-producing behavior they do not directly control. This project investigates which operators are successfully facilitating ZE truck visits under WAIRE, the mechanisms they use, and whether compliance patterns are equitably distributed across environmental justice (EJ) communities. The project combines quantitative analysis of compliance actions — linked to spatial CalEnviroScreen 4.0 scores and EV charging infrastructure data — with semi-structured interviews of warehouse operators and motor carriers. Findings will reveal whether ZE truck adoption is spatially concentrated among certain facilities, leaving the most-impacted EJ communities with continued diesel exposure, and what barriers prevent contracted carriers from adopting ZE trucks. Results may guide mitigation fee investments and support policy discussions on ISR expansion by providing evidence on ZE adoption mechanisms under ISRs.