(a) No person shall drive a motor vehicle at such a slow speed as to impede the normal and reasonable movement of traffic, except when reduced speed is necessary for safe operation.

(b) Whenever the commissioner of public safety or the commissioner of transportation or local authorities determine on the basis of any engineering and traffic investigation that slow speeds on any part of a road under their respective jurisdictions impede the normal and reasonable movement of traffic, such commissioners jointly, or such local authorities, may determine and declare a minimum speed limit below which no person shall drive a vehicle except when necessary for safe operation, and such limit shall be effective when posted upon fixed or variable signs.

(c) Upon roads, streets, or highways with two or more lanes allowing for movement in the same direction, no person shall continue to operate a motor vehicle in the passing lane once such person knows or should reasonably know that he or she is being overtaken in such lane from the rear by a motor vehicle traveling at a higher rate of speed. For purposes of this Code section, "passing lane" means the most left-hand lane other than a high occupancy vehicle lane.

(d) Subsection (c) of this Code section shall not apply:

(1) When traffic conditions or congestion make it necessary to drive in the passing lane;

(2) When inclement weather, obstructions, or hazards make it necessary to drive in the passing lane;

(3) When compliance with a law of this state or with an official traffic control device makes it necessary to drive in the passing lane;

(4) When a vehicle must be driven in the passing lane to exit or turn left;

(5) On toll highways, when necessary to pay a toll or use a pass;

(6) To authorized emergency vehicles engaged in official duties; or

(7) To vehicles engaged in highway maintenance and construction operations.