South Dakota State Regulations

Transportation Restrictions

Movement is restricted to daylight hours if one or more of the following conditions exist:

• An escort is required;
• The permit vehicle is not able to attain the speed of posted speed limits and is not able to maintain a speed within posted speed limits;
• The permit vehicle is wider than 10 feet;
• The permit vehicle is higher than 14 feet 6 inches;
• The permit vehicle is a single unit whose overall length exceeds 45 feet;
• The permit vehicle is a multiple-unit combination whose overall length exceeds 110 feet;
• The permit vehicle is a two-unit combination with an individual unit length longer than 60 feet;
• The permit vehicle is a three or more unit combination with an individual unit length longer than 48 feet;
• The permit vehicle will travel on state highways which are noninterstate and beyond a two-mile radius of an interstate highway interchange.
• Any time traffic, highway or other conditions indicate the need for such a restriction

An oversize permit is not valid when visibility is reduced to one-half mile or less by weather, dust, or smoke. An oversize or overweight permit is not valid when the road surface is slippery because of snow, ice, slush, or frost. Highway patrol officers may further restrict or prohibit operation under any oversize or overweight permit during periods when, in their judgment, weather conditions make continued operation unsafe.