### Question
How is the "trailer transporter towing unit" defined?


### Answer
The term **trailer transporter towing unit** is defined in *49 U.S.C. § 31111* as follows -

> a power unit that is not used to carry property when operating in a towaway trailer transporter combination

#### Citation:
  - *49 U.S.C. § 31111*
  - Heading: **SUBTITLE VI-MOTOR VEHICLE AND DRIVER PROGRAMS > PART B-COMMERCIAL > CHAPTER 311-COMMERCIAL MOTOR VEHICLE SAFETY > SUBCHAPTER II-LENGTH AND WIDTH LIMITATIONS**

