When streets, roads or improved highways within the City, or any portion of them are deemed by the City Manager to be insufficient to bear the existing traffic thereon, or when a street, road or improved highway would in the opinion of the City Manager be damaged or destroyed by heavy vehicles thereon, the maximum weight of vehicles and load or motor vehicles or the maximum speed, or both, as prescribed by law shall be reduced in the following manners:
(a) On State highways within the City, the Director of Transportation shall prescribe such reduction which shall not be more than 25%;
(b) On any street, road or highway within this City, the City Manager shall prescribe such reductions in vehicle weight and loads or the speed thereof, as the condition of said streets, roads or highways justifies.
The schedule of the reduction of maximum weights and speeds shall be filed, for the information of the public, in the office of the City Engineer. The City Manager, at least one day before the reduction becomes effective, shall cause to be placed and retained on such streets, roads or- highways, at both ends and at the points of intersection of principal roads during the period of such reduced limitation of weight, speed or both, signs of substantial construction which will conspicuously indicate the limitations of weight and speed which are allowed on the streets, roads, or highways, and the date on which such limitation shall go into effect.
(1969 Code 76.10)