RCW 81.28.240

Whenever the commission shall find, after such hearing, that the rules, regulations, practices, equipment, appliances, facilities or service of any such common carrier in respect to the transportation of persons or property are unjust, unreasonable, unsafe, improper, inadequate or insufficient, the commission shall determine the just, reasonable, safe, adequate, sufficient and proper rules, regulations, practices, equipment, appliances, facilities or service to be observed, furnished, constructed or enforced and be used in the transportation of persons and property by such common carrier, and fix the same by its order or rule.