49 CFR §390.38

1. (a)Federal requirements. A pipeline welding truck, as defined in paragraph (b) of this section, including the individuals operating such vehicle and the employer of such individual, is exempt from the following:
   1. (1)Any requirement relating to registration as a motor carrier, including the requirement to obtain and display a Department of Transportation number, in 49 CFR part 365 or 390.
   2. (2)Any requirement relating to driver qualifications in 49 CFR part 391.
   3. (3)Any requirement relating to driving of commercial motor vehicles in 49 CFR part 392.
   4. (4)Any requirement relating to parts and accessories and inspection, repair, and maintenance of commercial motor vehicles in 49 CFR parts 393 and 396.
   5. (5)Any requirement relating to hours of service of drivers, including maximum driving and on duty time, found in 49 CFR part 395.
2. (b)Definition. “Pipeline welding truck” means a motor vehicle that is travelling in the State in which the vehicle is registered or another State, is owned by a welder, is a pick-up style truck, is equipped with a welding rig that is used in the construction or maintenance of pipelines, and has a gross vehicle weight and combination weight rating and weight of 15,000 pounds or less.