The commission, upon its own initiative, may investigate all rates, joint rates, tolls, charges and exactions, classifications or schedules of rates or joint rates and rules and regulations of common carriers, except a motor carrier holding a certificate of public service. If after full hearing and investigation the commission finds that such rates, joint rates, tolls, charges or exactions, classifications or schedules of rates or joint rates or rules and regulations are unjust, unreasonable, unjustly discriminatory or unduly preferential, the commission shall have the power to fix and order substituted therefor such rates, tolls, charges, exactions, classifications or schedules of rates or joint rates and such rules and regulations as are just and reasonable.

If upon any investigation it is found that any such regulation, measurement, practice, act or service complained of is unjust, unreasonable, unreasonably inefficient or insufficient, unduly preferential, unjustly discriminatory, or otherwise in violation of this act or of the orders of the commission, or if it is found that any service is inadequate or that any reasonable service cannot be obtained, the commission may substitute therefor such other regulations, measurements, practices, service or acts, and make such order respecting any such changes in such regulations, measurements, practices, service or acts as are just and reasonable. When, in the judgment of the commission, public necessity and convenience require, the commission may establish just and reasonable concentration or other special rates, charges or privileges, but all such rates, charges and privileges shall be open to all users of a like kind of service under similar circumstances and conditions. Hearings shall be conducted in accordance with the provisions of the Kansas administrative procedure act, unless, in the case of a general investigation, for good cause, the commission orders otherwise.