### Question
How is the term urban bus defined?


### Answer
The term **urban bus** is defined in *42 U.S.C. § 7554* as the following:

> provided under regulations of the Administrator promulgated under section 7521(a) of this title.

#### Citation:
  - *42 U.S.C. § 7554*
  - Heading: **CHAPTER 85-AIR POLLUTION PREVENTION AND CONTROL > SUBCHAPTER II-EMISSION STANDARDS FOR MOVING SOURCES > Part A-Motor Vehicle Emission and Fuel Standards**

