1. (A)

   1. (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. (2) Enforcement tolerance is fifteen percent for a vehicle or trailer transporting unprocessed forest products only on noninterstate routes.
   3. (3) Enforcement tolerance is fifteen percent for a vehicle or trailer transporting sod only on noninterstate routes.

   4. (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

2. (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.

3. (C) Except on the interstate highway system:

   1. (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. (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. (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.