(a) A "driver," as defined for Motor Carrier Act jurisdiction (49 CFR parts 390-395; Ex parte No. MC-2, 3 M.C.C. 665; Ex parte No. MC-3, 23 M.C.C.1; Ex parte No. MC-4, 1 M.C.C. 1), is an individual who drives a motor vehicle in transporation which is, within the meaning of the Motor Carrier Act, in interstate or foreign commerce. (As to what is considered transportation in interstate or foreign commerce within the meaning of the Motor Carrier Act, see § 782.7 ). This definition does not require that the individual be engaged in such work at all times; it is recognized that even full-duty drivers devote some of their working time to activities other than such driving. "Drivers," as thus officially defined, include, for example, such partial-duty drivers as the following, who drive in interstate or foreign commerce as part of a job in which they are required also to engage in other types of driving or nondriving work: Individuals whose driving duties are concerned with transportation some of which is in intrastate commerce and some of which is in interstate or foreign commerce within the meaning of the Motor Carrier Act; individuals who ride on motor vehicles engaged in transportation in interstate or foreign commerce and act as assistant or relief drivers of the vehicles in addition to helping with loading, unloading, and similar work; drivers of chartered buses or of farm trucks who have many duties unrelated to driving or safety of operation of their vehicles in interstate transportation on the highways; and so-called "driver-salesmen" who devote much of their time to selling goods rather than to activities affecting such safety of operation. (Levinson v. Spector Motor Service,300 U.S. 649 ; Morris v. McComb,332 U.S. 422 ; Richardson v. James Gibbons Co., 132 F. (2d) 627 (C.A. 4), affirmed 319 U.S. 44 ; Gavril v. Kraft Cheese Co., 42 F. Supp. 702 (N.D. Ill.); Walling v. Craig, 53 F. Supp. 479 (D. Minn.); Vannoy v. Swift & Co. (Mo. S. Ct.), 201 S.W. (2d) 350; Ex parte No. MC-2, 3 M.C.C. 665; Ex parte No. MC-3, 23 M.C.C. 1; Ex parte Nos. MC-2 and MC-3, 28 M.C.C. 125; Ex parte No. MC-4, 1 M.C.C. 1. Cf. Colbeck v. Dairyland Creamery Co. (S.D. Supp. Ct.), 17 N.W. (2d) 262, in which the court held that the exemption did not apply to a refrigeration mechanic by reason solely of the fact that he crossed State lines in a truck in which he transported himself to and from the various places at which he serviced equipment belonging to his employer.)(b) The work of an employee who is a full-duty or partial-duty "driver," as the term "driver" is above defined, directly affects "safety of operation" within the meaning of section 204 of the Motor Carrier Act whenever he drives a motor vehicle in interstate or foreign commerce within the meaning of that act. (Levinson v. Spector Motor Service,330 U.S. 649 , citing Richardson v. James Gibbons Co., 132 F. (2d) 627 (C.A. 4), affirmed 319 U.S. 44 ; Morris v. McComb,332 U.S. 422 ; Ex parte No. MC-28, 13 M.C.C. 481, 482, 488; Ex parte Nos. MC-2 and MC-3, 28 M.C.C. 125, 139 (Conclusion of Law No. 2). See also Ex parte No. MC-2, 3 M.C.C. 665; Ex parte No. MC-3, 23 M.C.C. 1; Ex parte No. MC-4, 1 M.C.C. 1.) The Secretary has power to establish, and has established, qualifications and maximum hours of service for such drivers employed by common and contract carriers or passengers or property and by private carriers of property pursuant to section 204, of the Motor Carrier Act. (See Ex parte No. MC-4, 1 M.C.C. 1; Ex parte No. MC-2, 3 M.C.C. 665; Ex parte No. MC-3, 23 M.C.C. 1; Ex parte No. MC-28, 13 M.C.C. 481; Levinson v. Spector Motor Service,330 U.S. 649 ; Southland Gasoline Co. v. Bayley,319 U.S. 44 ; Morris v. McComb,332 U.S. 422 ; Safety Regulations (Carriers by Motor Vehicle), 49 CFR parts 390, 391, 395) In accordance with principles previously stated (see § 782.2 ), such drivers to whom this regulatory power extends are, accordingly, employees exempted from the overtime requirements of the Fair Labor Standards Act by section 13(b)(1). (Southland Gasoline Co. v. Bayley,319 U.S. 44 ; Levinson v. Spector Motor Service,330 U.S. 649 ; Morris v. McComb,332 U.S. 422 ; Rogers Cartage Co. v. Reynolds, 166 F. (2d) 317 (C.A. 6). This does not mean that an employee of a carrier who drives a motor vehicle is exempted as a "driver" by virtue of that fact alone. He is not exempt if his job never involves transportation in interstate or foreign commerce within the meaning of the Motor Carrier Act (see §§ 782.2 (d) and (e) , 782.7 , and 782.8 , or if he is employed by a private carrier and the only such transportation called for by his job is not transportation of property. (See § 782.2 . See also Ex parte No. MC-28, 13 M.C.C. 481, Cf. Colbeck v. Dairyland Creamery Co. (S. Ct. S.D.), 17 N.W. (2d) 262 (driver of truck used only to transport himself to jobsites, as an incident of his work in servicing his employer's refrigeration equipment, held non exempt).) It has been held that so-called "hostlers" who "spot" trucks and trailers at a terminal dock for loading and unloading are not exempt as drivers merely because as an incident of such duties they drive the trucks and tractors in and about the premises of the trucking terminal. (Keegan v. Ruppert (S.D. N.Y.), 7 Labor Cases, par. 61,726 6 Wage Hour Rept. 676, cf. Walling v. Silver Fleet Motor Express, 67 F. Supp. 846)