Is a motor vehicle carrier liable to a third person for harm caused by the negligence of an independent contractor?

who undertakes an activity (1) which can be lawfully carried on only under a public franchise or authority and (2) which involves possible danger to the public is liable to a third person for harm caused by the negligence of the carrier's independent contractor. [Citations.] Were the rule otherwise, a carrier could escape liability for the negligence of its independent contractors, thus reducing the incentive for careful supervision and depriving those who are injured of the financial responsibility of those to whom the privilege was granted. For these reasons, the carrier's duties are nondelegable.... (Serna, supra, at p. 1486, 2 Cal.Rptr.3d 835 ; see Gamboa v. Conti Trucking, Inc. (1993) 19 Cal.App.4th 663, 23 Cal.Rptr.2d 564 [motor carrier held liable to members of the public for harm caused by the negligence of the carrier's independent contractor].)