SECTION 1. Paragraph (1) of section eight of the Revised Motor Vehicle Law, as amended by Commonwealth Act Numbered One hundred and twenty-three, is further amended to read as follows:
"(1) The maximum allowable gross weight of a motor truck, passenger bus, or trailer, upon which to compute the registration fee therefor, shall be obtained by regulations to be promulgated by the Director of Public Works. The Director of Public Works shall, upon passage of this Act and from time to time thereafter as the needs of the service may require, prepare suitable tables of maximum allowable loads per wheel for different sizes and kinds of tires, and shall issue regulations for the proper use thereof subject to the approval of the Secretary of Public Works and Communications, as provided in sections four (a) hereof. The registration fees provided in this Act for trucks shall be payable in two equal installments, the first to be paid on or before the last day of February, and the second to be paid on or before the last day of August."