ROUSH CleanTech is the first OEM to receive the California Air Resources Board (CARB)'s 0.02 grams per brake horsepower-hour certification for 2022 model year vehicles. The new certification covers ROUSH CleanTech Gen 5 propane engines for Blue Bird school buses. The company has a propane engine that is 90% cleaner than national emissions requirements.

According to a news release from ROUSH, the certification is part of a proposed federal emissions regulation that goes into effect in 2027. ROUSH's engine achieves those proposed standards on nitrogen oxides (NOx). 

"Blue Bird is the leader in clean emissions school buses with over a decade of selling experience, and more than 20,000 clean and cost-reducing propane school buses on the road," said Matthew Stevenson, president and CEO of Blue Bird Corporation. "Equipping our buses with the lowest nitrogen oxide propane engine is great news for the environment, our customers, and our children."

Blue Bird propane school buses equipped with ultra-low NOx engines is expected to provide multiple advantages for school districts and bus contractors seeking funding from the Infrastructure Investment and Jobs Act's $2.5 billion Clean School Bus Program.