Drive on the roadway, not the shoulder
Question:Is it legal for a farmer to drive implements of husbandry in the main lane of traffic on a state highway when there is a shoulder available?
Answer:MN State Statute169.18 subd. 10 addresses slow-moving vehicles it says: Upon all roadways any vehicle proceeding at less than the normal speed of traffic at the time and place and under the conditions then existing shall be driven in the right-hand lane when available for traffic, or as close as practicable to the right-hand curb or edge of the roadway, except when overtaking and passing another vehicle proceeding in the same direction, or when preparing for a left turn at an intersection or into a private road or driveway, or when a specific lane is designated and posted for a specific type of traffic.
169.02Subd. 68. Roadway definition.
"Roadway" means that portion of a highway improved, designed, or ordinarily used for vehicular travel, exclusive of the sidewalk or shoulder.
The answer to your question is, yes they should travel in the traffic lane. The shoulder is anything outside of the white solid line of the roadway limits and is not considered part of the roadway.
I find nowhere that it requires or permits and implement of husbandry to travel on the shoulder. If the implement of husbandry travels on the shoulder, part of the vehicle is still in the traffic lane.
Almost always this creates a situation where another vehicle will try and squeeze by with oncoming traffic.
This situation puts three vehicles abreast and creates an unsafe passing condition. If the implement of husbandry travels in the traffic lane, traffic is required to slow down and pass in a safe manner when oncoming traffic is clear.
Not only for that reason but according to MnDOT shoulders are not constructed to the same specifications as the roadway and are not designed to carry traffic especially heavy weighted traffic.
Have a safe spring.
— Sgt Marc Erickson