(1) 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.
(2) On a freeway no motor vehicle, except emergency vehicles, shall be operated at a speed of less than forty miles per hour or at such a slow speed as to impede or block the normal and reasonable movement of traffic except when reduced speed is necessary for the safe operation of the motor vehicle because of weather, visibility, roadway, or traffic conditions. All vehicles entering or leaving such freeway from an acceleration or deceleration lane shall conform with the minimum speed regulations while they are within the roadway of the freeway. The minimum speed of forty miles per hour may be altered by the Department of Transportation or local authorities on freeways under their respective jurisdictions.
(3) Whenever the department or any local authority within its respective jurisdiction determines on the basis of an engineering and traffic investigation that low speeds on any part of a highway consistently impede the normal and reasonable movement of traffic, the department or such local authority 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.
(4) Vehicular, animal, and pedestrian traffic prohibited on freeways by the Nebraska Rules of the Road shall not travel on any other roadway where minimum speed limits of twenty miles per hour or more are posted.
(5) Any minimum speed limit which is imposed under subsection (2) or (3) of this section shall not be effective until appropriate and adequate signs are erected along the roadway affected by such regulation apprising motorists of such limitation.
(6) On any freeway, or other highway providing for two or more lanes of travel in one direction, vehicles shall not intentionally impede the normal flow of traffic by traveling side by side and at the same speed while in adjacent lanes. This subsection shall not be construed to prevent vehicles from traveling side by side in adjacent lanes because of congested traffic conditions.