What you need to know: California continues to lead the nation in replacing polluting diesel school buses with zero-emission models, thanks to nearly $1.4 billion in state investments, according to a new report. Unfortunately, federal funding for zero-emission school buses is in doubt. 

SACRAMENTO — A new report (//ww2.arb.ca.gov/sites/default/files/2025-12/FY%202025-26%20SB%201403%20Report_0.pdf) from the California Air Resources Board (CARB) shows that California remains the national leader in replacing aging, polluting school buses with zero-emission models. The report details how the state has invested more than $2 billion in school bus cleanup programs, including nearly $1.4 billion specifically for zero-emission school buses and infrastructure. The investments have supported the deployment of over 3,400 zero-emission school buses across more than 350 school districts. 

However, progress could be slowed by federal funding reductions. Last year, the Trump administration paused all awarded federal funds for clean school buses (https://www.claimsjournal.com/news/national/2025/04/21/330117.htm), creating uncertainty for school districts nationwide as they seek to deploy more zero-emission school buses. 

“Kids shouldn’t be poisoned by toxic fumes just to get to school,” said CARB Chair Lauren Sanchez. “Clean air and climate action aren’t optional — they’re how we protect our children’s health right now.” 

“Every day, hundreds of thousands of California kids are picked up and travel to school in dirty, polluting diesel buses, exposing our kids, and the neighborhoods where they live, to harmful emissions,” said California Energy Commission Commissioner Nancy Skinner. “Cleaning the air for these students and their communities is imperative, which makes these investments among the most important in California’s clean transportation portfolio.” 

According to the World Resources Institute, California leads the nation (https://www.wri.org/insights/where-electric-school-buses-us) in funding for electric school buses, with nearly four times as many funded buses as the next leading state, New York.  

CARB and the California Energy Commission are responsible for distributing state funds for school bus replacement including the necessary charging infrastructure and have done so for over a decade. In April 2024, the agencies announced $500 million in funding for 1,000 zero-emission school buses and associated charging equipment. 

The new report highlights the need for increased funding to meet the target of a fully zero-emission school bus fleet in California. School districts have used a combination of federal, state and local funds to modernize their school bus fleets. 

While some federal funds have since been released, the future of an additional $2 billion in federal support remains unclear. 

In 2022-23, California received about $146 million from the federal program. Current awards have not been finalized. 

Why it matters 

Diesel exhaust is a known carcinogen and poses serious health risks to children, including asthma, bronchitis, and impaired lung development. The time children spend in school bus commutes accounts for less than 10% of a child's day, yet riding in a diesel-fueled school bus has been found to contribute up to 33% of a child's daily exposure to some air pollutants according to a 2003 study (//ww2.arb.ca.gov/resources/documents/childrens-school-bus-exposure-and-mitigation-studies) funded by CARB.  

Zero-emission school buses eliminate tailpipe emissions, providing cleaner air for students and communities—especially in overburdened neighborhoods. These school buses also reduce greenhouse gas emissions and support California’s broader climate goals. 

How we got here 

California law requires the transition to zero-emission school buses by 2045, with all new school bus purchases required to be zero-emission where feasible starting in 2035 under Assembly Bill 579. The mandate is part of the state’s larger effort to become carbon neutral by 2045, in recognition that advances in the transportation sector are essential to meet the broader target.