CALSTART Media Contact: Jennifer Smith, jsmith@calstart.org

PASADENA, CA — Steady and sustained zero-emission bus (ZEB) adoption continues to grow nationwide despite ongoing procurement challenges, long vehicle lead times, and a constrained domestic manufacturing base, according to CALSTART’s updated Zeroing in on ZEBs report. This annual market update details the number of funded, ordered, delivered, and/or deployed transit ZEBs within the United States as of July 2025.

Key findings in this year’s report include:

• As of July 2025, a total of 8,116 full-size ZEBs have been funded, ordered, delivered, or deployed, representing 16 percent growth over the July 2024 count.
  • Nearly 1,400 small ZEBs have been adopted nationwide, representing 20% of year-over-year growth.
• Full-size ZEB adoption remains geographically widespread.
  • California continues to lead the nation (1,933 battery-electric buses and 690 fuel cell electric buses), followed by New York (829), Washington (521), Florida (519), and Massachusetts (292).
  • Notable year-over-year increases were observed in California, Washington, Indiana, Wisconsin, and Illinois.
• Battery-electric buses remain dominant (7,261 full-size vehicles have been adopted nationwide, representing a 13 percent increase from the previous reporting year), but fuel cell buses gain traction as agencies diversify their zero-emission mix.
• Fuel cell electric buses surged 49 percent nationwide, outpacing overall ZEB growth.
  • During the reporting period, fuel cell electric bus adoption reached 855 vehicles nationwide.
  • Growth was supported by new vehicles entering the market and fleet expansions in states with existing hydrogen programs and fueling investments.
  • California remains the largest market, followed by Nevada (52), New York (15), Illinois (14), and Ohio (14).
• More than 1,000 new ZEBs were added despite supply chain and manufacturing constraints.

“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.”

As reported, U.S. public transit agencies are continuing to add ZEBs into their business operations as part of broader efforts to modernize fleets, reduce transportation-related emissions, and improve air quality in local communities. Long-term policy frameworks that provide funding flexibility and phased-in implementation approaches prove critical to continued deployment. And with the support of grant programs — like the Low or No Emission (Low No) Program and Grants for Buses and Bus Facilities Program under the Infrastructure Investment and Jobs Act — vehicle and infrastructure incentives, and regulatory outlines, the ZEB market will continue its momentum.

Regardless of constant and growing challenges, including recent policy changes, the report confirms that ZEB adoption continues to expand across the country, signaling market opportunities for vehicles, infrastructure, and the workforce. Moving forward, progress will depend on offering and protecting funding opportunities, supporting domestic manufacturing capacity, and ensuring that transit agencies have the resources they need to advance the deployment of clean vehicle technologies.

Background

This report defines ZEBs as Class 3 and above battery-electric or fuel cell electric transit buses. Full-size ZEBs are defined as Class 7 or 8 transit buses that are 30 or more feet in length, and small ZEBs are defined as Class 3–6 transit buses that are shorter than 30 feet in length.

This report is based on CALSTART’s 30+ years of clean transit leadership and includes thorough data collection and detailed analysis from credible sources, including CALSTART’s leading transit subject matter experts.

Transit agencies, universities, and private entities developing vehicle and infrastructure technologies alike will find that this insightful report is a digestible, valuable resource that can help drive economic and job growth and advance clean transportation nationwide.

Hop on board CALSTART’s website today for more information on current bus initiatives.

About CALSTART

A mission-driven industry organization focused on transportation decarbonization and clean air for all, CALSTART has offices in New York, Michigan, Colorado, California, Florida, and Europe. CALSTART is uniquely positioned to build the national clean transportation industry by working closely with its nearly 200 member companies and building on the lessons learned from the major programs it manages for the State of California. CALSTART manages more than $1 billion in vehicle incentive and technical assistance programs in the United States and is leading a global effort to build the zero-emission commercial vehicle market.