### Question
How is the "diesel retrofit" defined?


### Answer
The term **diesel retrofit** is defined in *23 U.S.C. § 149* as follows -

> a replacement, repowering, rebuilding, after treatment, or other technology, as determined by the Administrator

#### Citation:
  - *23 U.S.C. § 149*
  - Heading: **CHAPTER 1-FEDERAL-AID HIGHWAYS**

