Zero-emission buses grow by 16% in the United States. Hydrogen sees strong momentum: +49%. The CALSTART report

The number of zero-emission buses continues to grow steadily across the United States and is now gaining ground in the Southeast and Midwest. According to CALSTART’s “Zeroing in on ZEBs” report, in 2025 the number of ZEBs increased by 16% compared to 2024, reaching 8,116 units, which means 1,088 additional vehicles compared with the 7,028 recorded the previous year.

CALSTART’s annual analysis of the zero-emission bus market reports the number of ZEBs that have been funded, ordered, delivered, and/or are already in service in the United States as of July 2025.

The growth trajectory is clear. In 2020 there were 2,790 ZEBs, which rose to 3,533 in 2021 and 5,480 in 2022. In 2023 the total surpassed 6,000 units (6,147), while 2024 marked the milestone of more than 7,000 buses. In 2025 the fleet exceeded 8,000 units. In short, the expected growth rate is at least about one thousand additional zero-emission buses per year.

CALSTART estimates that more than 15,000 ZEBs will be deployed by 2030. The forecast indicates around 9,200 buses in 2026, 10,500 in 2027, 12,000 in 2028, 13,700 in 2029, and over 15,000 by the end of the decade.

The growth of zero-emission buses in the United States is real and strong (more than +130% in about five years), but it does not yet represent a full transformation of the sector. ZEBs still account for only a small portion of the roughly 70,000 public transit buses in the U.S. fleet.

Zero-emission buses grow by 16% in the United States. Hydrogen sees strong momentum: +49%. The CALSTART report

California continues to lead the ranking, with 1,933 battery-electric buses and 690 hydrogen fuel-cell buses. So, more than 32% of new ZEBs in the United States are in California. The Golden State is followed by New York with 829, Washington with 521, and Massachusetts with 292.

Battery-electric buses remain the dominant technology, with 7,261 full-size vehicles deployed nationwide, representing +13% growth compared with the previous year.

However, hydrogen fuel-cell buses are gaining momentum, growing 49% nationwide and reaching 855 vehicles. Of these, 690 are in California, followed by Nevada (52), New York (15), and Illinois and Ohio (14 each).

Zero-emission policy program

Federal funding programs are playing a key role, including the Low or No Emission (Low-No) Program and the Grants for Buses and Bus Facilities Program, both established under the Infrastructure Investment and Jobs Act.

Together with incentives for vehicles and infrastructure and existing regulatory frameworks, these programs will continue to support the development of the ZEB market. Despite ongoing challenges—including changes in public policy—the report confirms that the adoption of zero-emission buses continues to expand, creating market opportunities.

«The data clearly shows ZEBs are no longer confined to early-adopter markets,” stated CALSTART’s Deputy Director of Transit, Mike Hynes. “We’re seeing sustained deployment nationwide — from traditional leaders like California to fast-growing states like Florida and Texas — even as agencies navigate longer timelines and a constrained domestic supply environment. That signals a durable market shift driven by transit agencies making long-term operational decisions. Continued progress and deployment at scale will depend on stable funding, flexible implementation pathways, and policies that support domestic manufacturing”.