It is hereby determined and declared as a matter of legislative finding and policy:
(1) That the traffic in the streets of the business section of metropolitan cities has become congested by the great number of motor vehicles entering and traversing such streets, and the trend is for an ever-increasing number of vehicles on such streets and that, unless appropriate action is taken, the congestion will become worse and constitute a public nuisance;
(2) That (a) the traffic congestion has created a hazard to life, limb, and property of those using such streets, (b) the free circulation of traffic of all kinds is necessary to the health, safety, and general welfare of the public, and (c) any impeding of the free flow of traffic might seriously affect the rapid and effective fighting of fires and the disposition of the police force and emergency vehicles;
(3) That there is insufficient space, on the streets or places adjacent thereto, to provide the required parking and that convenient offstreet parking would facilitate the free flow of traffic. The space below the surface of property, owned by the county for courthouse sites or other public uses, and the space below the surface of the streets could properly and beneficially be used for parking areas and such use would promote public safety, convenience, and welfare; and
(4) That providing for the relieving of traffic congestion is a matter of public welfare, of general public interest, statewide concern, and within the powers reserved to the state.