The tax levied under the provisions of RCW 35.95.040 shall be billed and collected at such times and in the manner fixed and determined by the corporate authorities in an ordinance levying the tax: PROVIDED, That the tax shall be designated and identified as a tax to be used solely for the operation, maintenance, and capital needs of the municipally owned or leased and municipally operated public transit system: AND PROVIDED FURTHER, That the corporate authorities may in connection with municipally owned or leased transit systems enter into contracts covering the operation and maintenance of such systems, including the employment of personnel.