It is hereby declared to be the purpose and policy of the Legislature in enacting this chapter to confer upon the Public Service Commission of West Virginia, in addition to all other powers conferred and duties imposed upon it by law, the power, authority and duty to supervise and regulate the transportation of persons and property for hire by motor vehicles upon or over the public highways of this state so as to: (a) Protect the safety and welfare of the traveling and shipping public in their use of transportation agencies by motor vehicle; (b) preserve, foster and regulate transportation and permit the coordination of transportation facilities; (c) provide the traveling and shipping public transportation agencies rendering stabilized service at just and reasonable rates. This chapter shall apply to persons and motor vehicles engaged in interstate commerce and to private commercial carriers by motor vehicle as defined in section two of this article, to the extent permitted by the Constitution and laws of the United States.