2023 South Carolina Code of Laws › Title 56 - Motor Vehicles › Chapter 5 - Uniform Act Regulating Traffic On Highways › Section 56-5-4140. Gross weight of vehicles, combinations of vehicles, and loads; exceptions.

(A)(1) The gross weight of a vehicle or combination of vehicles, operated or moved upon any section of highway, including the interstate highway system, except where the formula in item (4) allows for a higher weight, shall not exceed:
(The following weight limits do not include applicable tolerances)
(a) Single-unit vehicle with two axles 35,000 lbs. (b) Single-unit vehicle with three axles 46,000 lbs. (c) Single-unit vehicle with four axles 63,500 lbs.
except, on the interstate, vehicles must meet axle spacing requirements and corresponding maximum overall gross weights, not to exceed 63,500 lbs., in accordance with the table in item (4).
(d) Single-unit vehicle with five or more axles 65,000 lbs.
except, on the interstate, vehicles must meet axle spacing requirements and corresponding maximum overall gross weights, not to exceed 65,000 lbs., in accordance with the table in item (4).
(e) Combination of vehicles with three axle 50,000 lbs. (f) Combination of vehicles with four axles 65,000 lbs. (g) Combination of vehicles with five or more axles 73,280 lbs.
The gross weight imposed upon any highway or section of highway other than the interstate by two or more consecutive axles in tandem articulated from a common attachment to the vehicle and spaced not less than forty inches nor more than ninety-six inches apart shall not exceed thirty-six thousand pounds, and no one axle of any such group of two or more consecutive axles shall exceed the load permitted for a single axle. The load imposed on the highway by two consecutive axles, individually attached to the vehicle and spaced not less than forty inches nor more than ninety-six inches apart, shall not exceed thirty-six thousand pounds and no one axle of any such group of two consecutive axles shall exceed the load permitted for a single axle.
The ten percent enforcement tolerance specified in Section 56-5-4160 applies to the vehicle weight limits specified in item (1), and subsections (B) and (C). However, the gross weight on a single axle operated on the interstate may not exceed 20,000 pounds, including all enforcement tolerances; the gross weight on a tandem axle operated on the interstate may not exceed 35,200 pounds, including all enforcement tolerances; the overall gross weight for vehicles operated on the interstate may not exceed 75,185 pounds, including all enforcement tolerances except as provided in item (4).
(2) Enforcement tolerance is fifteen percent for a vehicle or trailer transporting unprocessed forest products only on noninterstate routes.
(3) Enforcement tolerance is fifteen percent for a vehicle or trailer transporting sod only on noninterstate routes.
(4) Vehicles with an overall maximum gross weight in excess of 75,185 pounds may operate upon any section of highway in the Interstate System up to an overall maximum of 80,000 pounds in accordance with the following:
The weight imposed upon the highway by any group of two or more consecutive axles may not, unless specially permitted by the Department of Public Safety, exceed an overall gross weight produced by the application of the following formula:
W = 500 (LN/N-1 + 12N + 36)
In the formula W equals overall gross weight on any group of two or more consecutive axles to the nearest 500 pounds, L equals distance in feet between the extreme of any group of two or more consecutive axles, and N equals number of axles in the group under consideration.
As an exception, two consecutive sets of tandem axles may carry a gross load of 68,000 pounds if the overall distance between the first and last axles of the consecutive sets of tandem axles is 36 feet or more. The formula is expressed by the following table:
Distance in feet Maximum load in pounds carried between the on any group of 2 extremes of any of 2 or more consecutive axles group of 2 or more consecutive axles 2 axles 3 axles 4 axles 5 axles 6 axles 7 axles 4 35,200 5 35,200 6 35,200 7 35,200 8 and less 35,200 35,200 more than 8 38,000 42,000 9 39,000 42,500 10 40,000 43,500 11 44,000 12 45,000 50,000 13 45,500 50,500 14 46,500 51,500 15 47,500 52,000 16 48,000 52,500 58,000 17 48,500 53,500 58,500 18 49,500 54,000 59,000 19 50,500 54,500 60,000 20 51,000 55,500 60,500 66,000 21 51,500 56,000 61,000 66,500 22 52,500 56,500 61,500 67,000 23 53,000 57,500 62,500 68,000 24 54,000 58,000 63,000 68,500 74,000 25 54,500 58,500 63,500 69,000 74,500 26 55,500 59,500 64,000 69,500 75,000 27 56,000 60,000 65,000 70,000 75,500 28 57,000 60,500 65,500 71,000 76,500 29 57,500 61,500 66,000 71,500 77,000 30 58,500 62,000 66,500 72,000 77,500 31 59,000 62,500 67,500 72,500 78,000 32 60,000 63,500 68,000 73,000 78,500 33 64,000 68,500 74,000 79,000 34 64,500 69,000 74,500 80,000 35 65,500 70,000 75,000 36 68,000 70,500 75,500 37 68,000 71,000 76,000 38 68,000 71,500 77,000 39 68,000 72,500 77,500 40 68,500 73,000 78,000 41 69,500 73,500 78,500 42 70,000 74,000 79,000 43 70,500 75,000 80,000 44 71,500 75,500 45 72,000 76,000 46 72,500 76,500 47 73,500 77,500 48 74,000 78,000 49 74,500 78,500 50 75,500 79,000 51 76,000 80,000 52 76,500 53 77,500 54 78,000 55 78,500 56 79,500 57 80,000
(B) On the interstate and noninterstate highways of this State, any over-the-road bus as defined in Title 49 of the United States Code, motorhome, or any vehicle which is regularly and exclusively used as an intrastate public agency transit passenger bus as defined in Title 49 of the United States Code, is excluded from the axle spacing requirements in subsection (A). However, these vehicles are limited to a maximum single axle weight limit of twenty-four thousand pounds, including all enforcement tolerances.
(C) Except on the interstate highway system:
(1) Dump trucks, dump trailers, trucks carrying agricultural products, concrete mixing trucks, fuel oil trucks, line trucks, and trucks designated and constructed for special type work or use are not required to conform to the axle spacing requirements of this section. However, the vehicle is limited to a weight of twenty thousand pounds for each axle plus scale tolerances and the maximum gross weight of these vehicles may not exceed the maximum weight allowed by subsection (A)(1) for the appropriate number of axles, plus allowable scale tolerances.
(2) Concrete mixing trucks which operate within a fifteen-mile radius of their home base are not required to conform to the requirements of this section. However, these vehicles are limited to a maximum load of the rated capacity of the concrete mixer, the true gross load not to exceed sixty-six thousand pounds. All of these vehicles shall have at least three axles each with brake-equipped wheels.
(3) Well-drilling, boring rigs, and tender trucks are not required to conform to the axle spacing requirements of this section. However, the vehicle is limited to seventy thousand pounds gross vehicle weight and twenty-five thousand pounds for each axle plus scale tolerances.
HISTORY: 1962 Code Section 46-664; 1952 Code Section 46-664; 1949 (46) 466; 1963 (53) 76, 122; 1967 (55) 561, 1024; 1970 (56) 2041; 1976 Act No. 569 Section 1; 1980 Act No. 500, Section 2; 1983 Act No. 151 Part III Section 28B; 1985 Act No. 199, Section 2; 1986 Act No. 373, Section 3; 1993 Act No. 164, Part II, Section 92; 1993 Act No. 181, Section 1433; 1996 Act No. 459, Section 192; 1996 Act No. 461, Section 5; 2008 Act No. 234, Section 3, eff upon approval (became law without the Governor's signature on May 22, 2008); 2009 Act No. 60, Section 1, eff June 2, 2009; 2016 Act No. 188 (H.4932), Section 3, eff May 25, 2016.