### Question
How does the law define out-of-service order?


### Answer
Under *49 U.S.C. § 5121*, **out-of-service order** is defined as:

> a requirement that an aircraft, vessel, motor vehicle, train, railcar, locomotive, other vehicle, transport unit, transport vehicle, freight container, potable tank, or other package not be moved until specified conditions have been met

#### Citation:
  - *49 U.S.C. § 5121*
  - Heading: **SUBTITLE III-GENERAL AND INTERMODAL PROGRAMS > CHAPTER 51-TRANSPORTATION OF HAZARDOUS MATERIAL**

