No operator of a vehicle upon any street of the city shall drive at a greater speed than is reasonable or prudent, having regard for the traffic, the use of the highways, and the prevailing conditions; providing, that the maximum rate of speed at any time shall be 20 miles per hour.
(`91 Code, § 71.05) (Ord. 8-1965, passed 10-26-65) Penalty, see 71.99