Georgia Code Title 40. Motor Vehicles and Traffic § 40-6-182

Whenever the commissioner of public safety or the commissioner of transportation shall determine upon the basis of an engineering and traffic investigation that any maximum speed set forth in this article is greater or less than is reasonable or safe under the conditions found to exist at any intersection or other place or upon any part of the state highway system, they may jointly determine and declare a reasonable and safe maximum speed limit at such place, which shall be effective when appropriate signs giving notice thereof are erected. Such a maximum speed limit may be declared to be effective at all times as are indicated upon such signs; and differing limits may be established for different times of day, different varying weather conditions, and other factors bearing on safe speeds, which shall be effective when posted upon appropriate fixed or variable signs. In no case shall the maximum speed limit for any highway be established at higher than the maximum speed limits set forth in Code Section 40-6-181 for that type of highway.