WASHINGTON, D.C. — Diesel Emissions Reduction Act (DERA) projects from 2008 to 2010 impacted more than 50,000 older diesel engines, according to a new report to Congress from the U.S. EPA.

"Second Report to Congress: Highlights of the Diesel Emissions Reduction Program,” released on Monday, also provides insight into the significant role of school buses in the DERA program.

In DERA’s fiscal year 2008, for example, 5,376 school buses were retrofitted or replaced to reduce emissions. That was the highest number for any type of vehicle, and it was about 42% of the total vehicles retrofitted or replaced in that fiscal year.

In 2009-10, an estimated 2,718 school buses were retrofitted or replaced, second to long-haul trucks at an estimated 5,580.

With Recovery Act DERA grants, an estimated 11,608 school buses were retrofitted or replaced, the most for any vehicle type.

DERA has contributed to some large-scale school bus projects. For example, the state of Mississippi cleaned up its entire fleet of eligible school buses, and now 100% of these buses meet the newest emission standards or are equipped with emission-control devices.

“Bolstered by DERA funding, Mississippi has raised additional money to replace 52 buses and to equip 2,000 more with emissions-reducing technologies,” according to the EPA report to Congress. “Nearly 500,000 children in Mississippi benefit each day from riding clean school buses.”

In 2009, EPA awarded its first Recovery Act grant under the DERA program to Colorado. The state received $1.73 million to retrofit nearly 1,000 school buses.

There have also been numerous smaller-scale projects involving school bus operations. For instance, the Soboba Band of Luiseño Indians in Riverside, Calif., received a $78,000 fiscal year 2009-10 grant to retrofit six school buses with diesel particulate filters.

To view the full report, go here.