Section 391.2 - General exceptions(a)Farm custom operation. The rules in this part, except for § 391.15(e) and (f) , do not apply to a driver who drives a commercial motor vehicle controlled and operated by a person engaged in custom-harvesting operations, if the commercial motor vehicle is used to-(1) Transport farm machinery, supplies, or both, to or from a farm for custom-harvesting operations on a farm; or(2) Transport custom-harvested crops to storage or market.(b)Apiarian industries. The rules in this part, except for § 391.15(e) and (f) , do not apply to a driver who is operating a commercial motor vehicle controlled and operated by a beekeeper engaged in the seasonal transportation of bees.(c)Certain farm vehicle drivers. The rules in this part, except for § 391.15(e) and (f) , do not apply to a farm vehicle driver except a farm vehicle driver who drives an articulated (combination) commercial motor vehicle, as defined in § 390.5 of this chapter. For limited exemptions for farm vehicle drivers of articulated commercial motor vehicles, see § 391.67 .(d)Covered farm vehicles. The rules in part 391, Subpart E-Physical Qualifications and Examinations-do not apply to drivers of "covered farm vehicles," as defined in 49 CFR 390.5 .(e)Pipeline welding trucks. The rules in this part do not apply to drivers of "pipeline welding trucks" as defined in 49 CFR 390.38(b) .76 FR 75487, Dec. 2, 2011, as amended at 78 FR 16195, Mar. 14, 2013; 78 FR 58483, Sept. 24, 2013; 81 FR 47720, July 22, 2016