Arizona Revised Statutes Title 28. Transportation § 28-704. Minimum speed limits;  requirement to turn off roadway

A. A person shall not drive a motor vehicle at such a slow speed as to impede or block the normal and reasonable movement of traffic except when either of the following applies:

B. If the director or local authorities within their respective jurisdictions determine on the basis of an engineering and traffic investigation that slow speeds on any part of a highway consistently impede the normal and reasonable movement of traffic, the director or local authority may determine and declare a minimum speed limit below which a person shall not drive a vehicle except when necessary for safe operation or in compliance with law.

C. If a person is driving a vehicle at a speed less than the normal flow of traffic at the particular time and place on a two-lane highway where passing is unsafe and if five or more vehicles are formed in a line behind the vehicle, the person shall turn the vehicle off the roadway at the nearest place designated as a turnout by signs erected by the director or a local authority, or wherever sufficient area for a safe turnout exists, in order to allow the vehicles following to proceed.  For the purposes of this subsection: