# Summary of South Dakota Speed Zone Rule Changes The Department of Transportation updated speed zone rules across six counties—Beadle, Lawrence, Fall River, Hamlin, Hanson, and Jones—to standardize measurements, clarify road location descriptions, and adjust speed limits in specific areas. Key changes include extending 45 mph zones in Wolsey and Huron (Beadle County), adding a new 45 mph transition zone at Cheyenne Crossing (Lawrence County), removing a truck speed restriction on U.S. Highway 14A (Lawrence County), and adding a 45 mph transition zone on U.S. Highway 83 near Murdo (Jones County). All distance measurements throughout these rules were rounded to the nearest tenth of a mile, reference points were updated to use street names and landmarks instead of section-township-range coordinates, and minor speed limit adjustments were made to ensure smoother transitions between zones.
AI-generated from the adopted rule text — verify against the official documents.
70:01:02:04 – Beadle County speed zone rule. The South Dakota Department of Transportation proposes to extend the current 45 miles per hour (mph) speed limit on U.S. Highway 14 on the south edge of Wolsey and the current 45 mph speed limit on Highway 37 in Huron. The department is also clarifying the starting points for speed zones and revising speed zone measurements to the nearest one-tenth of a mile. 70:01:02:09 – Lawrence County speed zone rule. On U.S. Highway 14A and U.S. Highway 85 at and around Cheyenne Crossing in Lawrence County, the department plans to add a 45 mph transition speed zone. The department is also eliminating a truck speed limit on U.S. Highway 14A east of Cheyenne Crossing. Furthermore, the department is correcting minor deviations in speed zone distances, revising measurements to the nearest one-tenth of a mile, and eliminating redundancy in the rule. 70:01:02:27 – Fall River County speed zone rule. On State Trunk Highway 79 in Fall River County, the department proposes to extend a 55 mph speed zone. The department is also correcting minor deviations in speed zone distances, clarifying the starting points for speed zone rules, and revising speed zone measurements to the nearest one-tenth of a mile. 70:01:02:32 – Hamlin County speed zone rule. The department proposes to extend the current 25 mph speed zone on State Trunk Highway 21 on the east edge of Hayti. The department is also revising speed zone measurements to the nearest one-tenth of a mile. 70:01:02:34 – Hanson County speed zone rule. On State Trunk Highway 262 in Hanson County, the department plans to lengthen the existing 45 mph speed zone at the I-90 interchange. The department is also correcting naming conventions and revising measurements to the nearest one-tenth of a mile. 70:01:02:41 – Jones County speed zone rule. The department is adding a 45 mph transition speed zone on U.S. Highway 83 in and around Murdo. The department is also eliminating redundancy in the rule, clarifying the starting and ending points for speed zones, and revising speed zone measurements to the nearest one-tenth of a mile.