South Dakota Truck Weight and Size Limits
Legal limits for a truck in South Dakota without a permit: Interstate axle and gross weights, height, width, and semitrailer length, each with its official source.
South Dakota limits at a glance
| Limit | South Dakota | Source |
|---|---|---|
| Interstate gross weight | 80,000 lb | 23 CFR 658.17, Weight (eCFR) |
| Interstate single axle | 20,000 lb | 23 CFR 658.17, Weight (eCFR) |
| Interstate tandem axle | 34,000 lb | 23 CFR 658.17, Weight (eCFR) |
| Width (National Network) | 102 in | 23 CFR 658.15, Width (eCFR) |
| Height | 14 ft | S.D. Codified Laws § 32-22-14 |
| Semitrailer length | 53 ft on the Interstate and state trunk highway system | S.D. Codified Laws § 32-22-8.1(1) |
| Grandfathered semitrailer length | 53 ft | 23 CFR part 658, Appendix B, Grandfathered Semitrailer Lengths (eCFR) |
Interstate weight limits
Federal law sets the Interstate limits at 20,000 lb on a single axle, 34,000 lb on a tandem, and 80,000 lb gross, with the bridge formula on every axle group (23 CFR 658.17). States may keep higher limits they had before the federal limits took effect ("grandfather rights").
Grandfathered: up to 129,000 lb GVW on listed routes, including segments of US-14, US-85, US-281, and SD-50.
FHWA on South Dakota: South Dakota has a grandfather provision under Federal law (23 CFR Part 658, Appendix C) to allow vehicles to operate up to 129,000 lbs. GVW on parts of the interstate system. See the Routes section for a full description of the routes to which this grandfather provision applies.
Bridge formula check with South Dakota limits
A 5-axle tractor-trailer is filled in. Change the spacings and weights to match your rig; the limits for single axles, tandems, and gross are South Dakota's Interstate limits.
Your result
South Dakota limits off the Interstate
FHWA's summary of South Dakota law for trucks in regular operation (no permit), including non-Interstate highways. It reflects state law as of October 1, 2012; check the state for later changes.
- Single axle
- 20,000 lbs.
- Tandem axle
- 34,000 lbs.
- Tridem axle
- Per FBF
- Gross weight
- 80,000 lbs. on Interstate highways (except grandfathered routes) / Subject to State bridge formula on non-Interstate highways
- Other
- 600 lbs. per inch of tire width on steering axles and axles with dual tires* / 500 lbs. per inch of tire width on all other axles (S.D. Codified Laws Ann. §32-22-21)
Height, width, and length
- Width: 102 inches. States may not set a width limit of more or less than 102 inches on the National Network (23 CFR 658.15(a)). Permits can allow wider loads.
- Height: 14 ft. There is no federal height limit; each state sets its own.
- Semitrailer length: 53 ft on the Interstate and state trunk highway system
- Grandfathered semitrailer length: 53 ft. The minimum semitrailer length the state must allow in a tractor-semitrailer combination on the National Network, based on lengths legal in the state on December 1, 1982. Federal law also requires at least 48 ft (23 CFR 658.13(b)(1)).
Over these limits you need a permit. South Dakota oversize/overweight permits (605-224-7364).
South Dakota compared with neighboring states
| State | Gross | Single | Tandem | Height | Semitrailer |
|---|---|---|---|---|---|
| South Dakota | 80,000 lb | 20,000 lb | 34,000 lb | 14 ft | 53 ft on the Interstate and state trun… |
| Iowa | 80,000 lb | 20,000 lb | 34,000 lb | 13 ft 6 in | 53 ft in a truck tractor-semitrailer c… |
| Minnesota | 80,000 lb | 20,000 lb | 34,000 lb | 13 ft 6 in | 48 ft |
| Montana | 80,000 lb | 20,000 lb | 34,000 lb | 14 ft | 53 ft |
| Nebraska | 80,000 lb | 20,000 lb | 34,000 lb | 14 ft 6 in | 53 ft including load |
| North Dakota | 80,000 lb | 20,000 lb | 34,000 lb | 14 ft | 53 ft |
Sources
Source: 23 CFR 658.17, Weight (eCFR) · Last verified Sep 28, 2026
Source: FHWA, Compilation of Existing State Truck Size and Weight Limit Laws (Report to Congress, May 2015), Appendix A: South Dakota · Effective Oct 1, 2012 · Last verified Sep 28, 2026
Source: FHWA, Compilation of Existing State Truck Size and Weight Limit Laws (Report to Congress, May 2015), Appendix B: Summary of State Exceptions to Federal Truck Weight Limits · Effective Oct 1, 2012 · Last verified Sep 28, 2026
Source: 23 CFR 658.15, Width (eCFR) · Last verified Sep 28, 2026
Source: 23 CFR part 658, Appendix B, Grandfathered Semitrailer Lengths (eCFR) · Last verified Sep 28, 2026
Source: S.D. Codified Laws § 32-22-8.1(1) · Last verified Sep 28, 2026
Source: S.D. Codified Laws § 32-22-14 · Last verified Sep 28, 2026
Source: FHWA, Oversize/Overweight Load Permits: State permit contacts · Last verified Sep 28, 2026
Limits change, and cities, counties, and posted bridges can set lower ones. Check with South Dakota before you run a load near the limits. Page data last verified Sep 28, 2026.