The
Minimum Speed sign indicates that it is illegal to drive at a lower speed
except when necessary for safe operation or in compliance with law. It is
usded where engineering and traffic investigations show that slow speeds
on a highway consistantly impede the normal and reasonable movement of traffic.
Minimum Speed signs are posted in the same manner as Maximum Speed signs.
When both Maximum and Minimum Speed signs are used, the Minimum Speed sign
must be installed below the Maximum Speed sign.