Permits
Oversize permits are valid for 3 days. Driver must have permit prior to entering the state.

Operating Time
Travel is allowed one-half hour before sunrise to one-half hour after sunset, including Saturday and Sunday. Overweight only loads and loads not exceeding 10′ wide, 14’6″ high, 110′ overall length traveling on interstate highways are allowed continuous travel.

Restrictions
SEASONAL LOAD (WEIGHT) RESTRICTIONS: Loads are subject to spring weight restrictions during the period of February 15th to April 30th.

Speed Limit

Maximum posted limits unless otherwise specified on permit.

Legal Dimensions
The vehicle must have the following characteristics:

Width: 8’6”
Height: 14”
Length: 53′ semi-trailer, overall length not limited.
Overhang: 3′ front, 4′ rear
Weight: 80,000 Gross; Single – 20,000; Tandem – 34,000; Tridem – 42,000
Routine South Dakota Oversize Permit Limits
Width: 16′
Height: 16′
Length: Depends on route
Weight: Single – 24,000; Tandem – 46,000; Tridem – 60,000; Quad – 68,000

Escorts
Width: On Interstate Highways: Over 16′ – 1 escort. On most State Highways: Over 20′ – 1 escort. Multiple escorts are required if the load extends more than two feet into adjacent driving or passing lanes, or if traffic cannot pass without the permit vehicle or passing vehicle driving on the shoulder of the road.
Length: Normally no requirements.
Height: Normally no requirements.
*Note: Highways 16 and 18 in the Black Hills area requires 1 escort of loads exceeds 10′

Security Measures
“Oversize Load” signs are required on all loads exceeding 12′ wide or 95′ long. Travel at night requires reflectorized or lighted signs. All oversized vehicles and loads must display flags that are 18” square. They must be attached to all corners of vehicles or loads wider than 8’6” and to corners of any load extending beyond the width of the hauling vehicle. Flags are also to be attached to load projecting more than 3 feet in front of the vehicles front bumper, or more than 4 feet beyond the rear of the trailer. If the front or rear projection is two feet or less, at least one flag is needed on the projection. Two flags are required on the projection if it is over 2 feet in width.

Load overhang must have proper lighting for nighttime running with amber lights, red lights, and reflectors.