(a) Every motor carrier, its officers, drivers, agents, representatives, and employees directly concerned with the inspection or maintenance of commercial motor vehicles must be knowledgeable of and comply with the rules of this part.(b) Every intermodal equipment provider, its officers, agents, representatives, and employees directly concerned with the inspection or maintenance of intermodal equipment interchanged or offered for interchange to motor carriers must be knowledgeable of and comply with the rules of this part.(c) This part does not apply to "covered farm vehicles," as defined in 49 CFR 390.5 , or to the drivers of such vehicles.(d) The rules in this part do not apply to "pipeline welding trucks" as defined in 49 CFR 390.38(b) . 73 FR 76823 , Dec. 17, 2008, as amended at 78 FR 16195 , Mar. 14, 2013; 81 FR 47722 , July 22, 2016