A. Compliance; Exceptions: No vehicle shall be driven at a greater speed than twenty five (25) miles per hour in the city, except:
1. On designated and numbered state and federal highways, the maximum is as posted;
2. Emergency vehicles being lawfully driven as provided in this title;
3. When a different speed limit is otherwise designated and posted; or
4. When a different speed limit is established and posted as required in this title.
B. City Authority; Posting Signs: City personnel, subject to such direction as the mayor and city council may give, by motion or resolution, may reduce or increase the speed limits provided in this title, and when so done, appropriate signs shall be placed on such streets or parts of streets indicating the lower or higher speed limit. (1990 Code § 15-401)