Section 6
SEC. 6. In every case the Department of Public Works and Communications shall approve the fairness and equity of the tolls or fees, as the case may be, or the schedule of such tolls and fees, submitted by the persons or associations of persons contracting for any such national highway, road, bridge, public market, irrigation system and any other self-liquidating public improvement, and shall decide whether said tolls, fees or schedules are to the public; and no tolls, fees or schedules thereof shall be put in force and operation by the person or association of persons contracting such public improvements, until such tolls, fees or schedules thereof shall have been so approved; and the Department of Public Works and Communications may from time to time change and revise such tolls, fees and schedules thereof.