The amount of coins required to be deposited in parking meters as provided herein is hereby levied and assessed as a fee to provide for the proper regulation, control and inspection of traffic upon the public streets, and to cover the cost of supervising, regulating and inspecting the parking of vehicles in the parking meter zones provided for herein, the cost of placing and maintaining lines or markings, designating parking spaces in parking meter zones, and the cost of the purchase, supervision, protection, inspection, installation, operation, maintenance, control and use of the parking meters installed hereunder, and the special fund in which such fees shall be placed shall be used for those purposes and for the maintenance and establishment of parking facilities and for the upkeep and maintenance of public thoroughfares in the city.
(`73 Code, 20.147, § 10.17)