>>510117970“The right of a citizen to travel upon the highway and transport his property thereon, in the ordinary course of life and business, differs radically and obviously from that of one who makes the highway his place of business and uses it for private gain, in the running of a stage coach or omnibus. The former is the usual and ordinary right of a citizen, a common right, a right common to all, while the latter is special, unusual, and extraordinary.” - Ex parte Dickey
18 U.S.C. § 31 - U.S. Code - Crimes and Criminal Procedure § 31. Definitions
(6) Motor vehicle.--The term “motor vehicle” means every description of carriage or other contrivance propelled or drawn by mechanical power and used for commercial purposes on the highways in the transportation of passengers, passengers and property, or property or cargo.
(10) Used for commercial purposes.--The term “used for commercial purposes” means the carriage of persons or property for any fare, fee, rate, charge or other consideration, or directly or indirectly in connection with any business, or other undertaking intended for profit.