31-5-304. Minimum speed limits.
(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 or in compliance with law.
(b) Whenever the superintendent determines on the basis of an engineering and a traffic investigation that slow speeds on any part of a highway consistently impede the normal and reasonable movement of traffic, the superintendent may determine and declare a minimum speed limit below which no person shall drive a vehicle except when necessary for safe operation or in compliance with law and that limit is effective when posted upon appropriate fixed or variable signs. A local authority may make the determination permitted under this subsection by complying with rules adopted by the department for this purpose, which rules shall adopt standards consistent with national practices.
(c) Notwithstanding any minimum speed that may be authorized and posted pursuant to this section, no person shall operate a vehicle in the extreme left-hand lane of a controlled-access highway for a prolonged period in a manner which impedes the flow of other traffic traveling at a lawful rate of speed.