Roush CleanTech earns ultra-low NOx certification from CARB

January 20, 2022 By    
Photo: Roush CleanTech

Photo: Roush CleanTech

Roush CleanTech received the California Air Resources Board’s (CARB) 0.02 grams per brake horsepower-hour certification for 2022 model year vehicles.

According to the company, it is the first original equipment manufacturer to receive the certification.

The optional ultra-low CARB certification is 90 percent cleaner than current emissions standards for nitrogen oxides (NOx). The new engine certification covers the Roush CleanTech Gen 5 propane engines for Blue Bird school buses.

This is the second time Roush CleanTech has earned the ultra-low NOx certification, previously for its 6.8L V10 propane engine in 2018. The certification is part of a proposed federal emissions regulation that goes into effect in 2027.

“Since the introduction of our Ford 7.3L V8 propane engine in 2020, our team has worked tirelessly to gain this emissions certification,” says Todd Mouw, president of Roush CleanTech. “We remain committed to providing cost-efficient, advanced vehicle solutions for the school bus market that reduce environmental impact.”

Blue Bird propane school buses equipped with ultra-low NOx engines will provide multiple advantages for school districts and school bus contractors seeking funding from the Infrastructure Investment and Jobs Act’s $2.5 billion Clean School Bus Program, the company says. Funding through the program is scheduled to be released in 2022 through 2026, with project implementation as soon as next year.

“Equipping our buses with the lowest nitrogen oxide propane engine is great news for the environment, our customers and our children,” says Matthew Stevenson, president and CEO of Blue Bird.

About the Author:

Danielle Pesta is the senior digital media manager for North Coast Media, the parent company of LP Gas. She can be reached at

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