§ 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.