Iowa § 321.463 - 321.463 Maximum gross weight — exceptions — penalties.

§ 321.463. 321.463 Maximum gross weight — exceptions — penalties.

1. An axle may be divided into two or more parts, except that all parts in the same vertical transverse plane shall be considered as one axle. 2. The gross weight on any one axle of a vehicle, or of a combination of vehicles, operated on the highways of this state, shall not exceed twenty thousand pounds on an axle equipped with pneumatic tires, and shall not exceed fourteen thousand pounds on an axle equipped with solid rubber tires. The gross weight on any tandem axle of a vehicle, or any combination of vehicles, shall not exceed thirty-four thousand pounds on an axle equipped with pneumatic tires. This subsection does not apply to implements of husbandry. 3. Notwithstanding other provisions of this chapter to the contrary, indivisible loads operating under the permit requirements of sections 321E.7, 321E.8, 321E.9, 321E.29A, and 321E.29B, and divisible loads operating under the permit requirements of section 321E.26, shall be allowed a maximum of twenty thousand pounds per axle. 4. a. (1) Notwithstanding any provision of this section to the contrary, the weight on any one axle of a self-propelled implement of husbandry used exclusively for the application of organic or inorganic plant food materials, agricultural limestone, or agricultural chemicals operated on the highways of this state shall not exceed twenty-five thousand pounds. (2) A self-propelled implement of husbandry used exclusively for the application of organic or inorganic plant food materials, agricultural limestone, or agricultural chemicals shall comply with the other provisions of this section and chapter when operated over a bridge in this state, other than any provision limiting the weight on any one axle to less than twenty-five thousand pounds. A local authority may issue a special permit, based on a statewide standard developed by the department, allowing the operation over a bridge within its jurisdiction of such a self-propelled implement of husbandry with a weight in excess of the weights allowed under this chapter. b. (1) Notwithstanding any provision of this section to the contrary, the weight on any one axle of a fence-line feeder, grain cart, or tank wagon operated on the highways of this state shall not exceed twenty-four thousand pounds from February 1 through May 31 or twenty-eight thousand pounds from June 1 through January 31, provided, however, that the maximum gross vehicle weight of the fence-line feeder, grain cart, or tank wagon shall not exceed ninety-six thousand pounds. (2) Notwithstanding any provision of this section to the contrary, a tracked implement of husbandry operated on the highways of this state shall not have a maximum gross weight in excess of ninety-six thousand pounds. (3) A fence-line feeder, grain cart, tank wagon, or tracked implement of husbandry shall comply with the other provisions of this section and chapter when operated over a bridge in this state. A local authority may issue a special permit, based on a statewide standard developed by the department, allowing the operation over a bridge within its jurisdiction of a fence-line feeder, grain cart, tank wagon, or tracked implement of husbandry with a weight in excess of the weights allowed under this chapter. (4) For purposes of this paragraph “b”: (a) “Highway” does not include a bridge. (b) “Fence-line feeder, grain cart, or tank wagon” means any fence-line feeder, grain cart, or tank wagon. 5. a. Notwithstanding any provision of law to the contrary, a motor vehicle equipped with an engine fueled primarily by natural gas may exceed any applicable maximum gross weight limit under this chapter, up to a maximum gross weight of eighty-two thousand pounds, by an amount equal to the difference between the weight of the vehicle attributable to the natural gas tank and fueling system installed in the vehicle and the weight of a comparable diesel fuel tank and fueling system. b. Notwithstanding any provision of law to the contrary, a motor vehicle described in paragraph “a” equipped with an auxiliary power or idle reduction technology unit that reduces fuel use and emissions during engine idling may exceed any applicable maximum gross weight limit under this chapter by five hundred fifty pounds or the weight of the auxiliary power or idle reduction technology unit, whichever is less. This paragraph “b” Thu Dec 11 19:42:09 2025 Iowa Code 2026, Section 321.463 (70, 3) §321.463, MOTOR VEHICLES AND LAW OF THE ROAD 2 does not apply unless the operator of the vehicle provides to the department of public safety a written certification of the weight of the auxiliary power or idle reduction technology unit, demonstrates or certifies to the department of public safety that the idle reduction technology unit is fully functional at all times, and carries with the operator the written certification of the weight of the auxiliary power or idle reduction technology unit in the vehicle at all times to present to law enforcement in the event the vehicle is suspected of violating any applicable weight restrictions. 6. a. The maximum gross weight allowed to be carried on a vehicle or combination of vehicles on highways which are part of the primary road system is as follows: Thu Dec 11 19:42:09 2025 Iowa Code 2026, Section 321.463 (70, 3) 3 MOTOR VEHICLES AND LAW OF THE ROAD, §321.463 MAXIMUM GROSS WEIGHT TABLE — PRIMARY HIGHWAYS Distance in feet 4 5 6 7 8 8’1” 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 2 Axles 34,000 34,000 34,000 34,000 34,000 38,000 39,000 40,000 3 Axles 34,000 34,000 42,000 42,500 43,500 44,000 45,000 45,500 46,500 47,000 48,000 48,500 49,500 50,000 51,000 51,500 52,500 53,000 54,000 54,500 55,500 56,000 57,000 57,500 58,500 59,000 60,000 4 Axles 48,500 49,500 50,000 50,500 51,500 52,000 52,500 53,500 54,000 54,500 55,500 56,000 56,500 57,500 58,000 58,500 59,500 60,000 60,500 61,500 62,000 62,500 63,500 64,000 64,500 65,500 68,000 68,000 68,000 68,000 68,500 69,500 70,000 70,500 71,500 72,000 72,500 73,500 74,000 74,500 75,500 76,000 76,500 77,500 78,000 78,500 79,500 80,000 5 Axles 56,000 57,000 57,500 58,000 58,500 59,000 60,000 60,500 61,000 61,500 62,500 63,000 63,500 64,000 65,000 65,500 66,000 66,500 67,500 68,000 68,500 69,500 70,000 70,500 71,000 72,000 72,500 73,000 73,500 74,000 75,000 75,500 76,000 76,500 77,500 78,000 78,500 79,000 80,000 6 Axles 64,000 65,000 65,500 66,000 66,500 67,000 68,000 68,500 69,000 69,500 70,000 71,000 71,500 72,000 72,500 73,000 74,000 74,500 75,000 75,500 76,000 77,000 77,500 78,000 78,500 79,000 80,000 7 Axles 71,500 72,500 73,000 73,500 74,000 74,500 75,000 76,000 76,500 77,000 77,500 78,000 78,500 79,500 80,000 b. The maximum gross weight allowed to be carried on a vehicle or combination of vehicles on nonprimary highways is as follows: Thu Dec 11 19:42:09 2025 Iowa Code 2026, Section 321.463 (70, 3) §321.463, MOTOR VEHICLES AND LAW OF THE ROAD 4 NONPRIMARY HIGHWAYS — MAXIMUM GROSS WEIGHT TABLE Distance in feet 4 5 6 7 8 8’1” 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 2 Axles 34,000 34,000 34,000 34,000 34,000 38,000 39,000 40,000 3 Axles 34,000 34,000 42,000 42,500 43,500 44,000 45,000 45,500 46,500 47,000 48,000 48,500 49,500 50,000 51,000 51,500 52,500 53,000 54,000 54,500 55,500 56,000 57,000 57,500 58,500 59,000 60,000 4 Axles 45,000 46,000 47,000 48,000 49,000 50,000 51,000 52,000 53,000 54,500 55,500 56,000 56,500 57,500 58,000 58,500 59,500 60,000 60,500 61,500 62,000 62,500 63,500 64,000 64,500 65,500 68,000 68,000 68,000 68,000 68,500 69,500 70,000 70,500 71,500 72,000 72,500 73,500 74,000 74,500 75,500 76,000 76,500 77,500 78,000 78,500 79,500 80,000 5 Axles 48,500 49,500 50,500 51,500 52,500 53,500 54,500 55,500 56,500 57,500 58,500 59,500 60,500 61,500 62,500 63,500 64,500 65,500 66,500 67,500 68,500 69,500 70,000 70,500 71,000 72,000 72,500 73,000 73,500 74,000 75,000 75,500 76,000 76,500 77,500 78,000 78,500 79,000 80,000 6 Axles 7 Axles 54,000 55,000 56,000 57,000 58,000 59,000 60,000 61,000 62,000 63,000 64,000 65,000 66,000 67,000 68,000 69,000 70,000 71,000 72,000 73,000 74,000 75,000 76,000 77,000 78,000 79,000 80,000 78,000 79,000 80,000 c. (1) The maximum gross weight allowed to be carried on a commercial motor vehicle on noninterstate highways, provided the vehicle is operated by a person with a commercial driver’s license valid for the vehicle operated unless section 321.176A applies, is as follows: Thu Dec 11 19:42:09 2025 Iowa Code 2026, Section 321.463 (70, 3) 5 MOTOR VEHICLES AND LAW OF THE ROAD, §321.463 NONINTERSTATE HIGHWAYS MAXIMUM GROSS WEIGHT TABLE COMMERCIAL MOTOR VEHICLE Distance in feet 6 Axles 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 80,500 81,000 81,500 82,000 83,000 83,500 84,000 84,500 85,000 86,000 86,500 87,000 87,500 88,000 89,000 89,500 90,000 7 Axles 80,500 81,500 82,500 83,500 84,000 85,000 86,000 87,000 88,000 88,500 89,500 90,500 91,500 92,000 93,000 94,000 95,000 95,500 96,000 (2) Notwithstanding any provision of this section to the contrary, the maximum gross weight allowed to be carried on a noninterstate highway by a livestock vehicle with five axles, a minimum distance in feet between the centers of the first and fifth axles of sixty-one feet, and a minimum distance between the two rear axles of at least eight feet and one inch is eighty-six thousand pounds. d. For the purposes of the maximum gross weight tables in paragraphs “a”, “b”, and “c”, distance in feet is the measured distance in feet between the centers of the extreme axles of any group of axles, rounded to the nearest whole foot. e. (1) The maximum gross weight allowed to be carried on a tracked implement of husbandry when operated on a noninterstate highway bridge is as follows: NONINTERSTATE HIGHWAY BRIDGES MAXIMUM GROSS WEIGHT TABLE TRACKED IMPLEMENTS OF HUSBANDRY Length of Track in Feet Weight in Pounds 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Thu Dec 11 19:42:09 2025 34,000 34,000 34,000 34,000 42,000 42,500 45,000 46,000 47,000 48,500 49,500 50,500 51,500 54,000 55,000 56,000 57,000 Iowa Code 2026, Section 321.463 (70, 3) §321.463, MOTOR VEHICLES AND LAW OF THE ROAD 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 6 58,000 59,000 60,000 61,000 62,000 63,000 64,000 65,000 66,000 67,000 68,000 69,000 70,000 71,000 72,000 73,000 74,000 75,000 76,000 77,000 78,000 79,000 80,000 (2) “Length of track in feet” means the length of track on one side of the tracked implement of husbandry which is in contact with the ground or roadway surface. 7. The weight on any one axle, including a tandem axle, of a vehicle which is transporting livestock on highways not part of the interstate system may exceed the legal maximum weight given in this chapter providing that the gross weight on any particular group of axles on such vehicle does not exceed the gross weight allowable under this chapter for such groups of axles. 8. The weight on any one axle, including a tandem axle, of a vehicle which is transporting raw materials from a designated borrow site to a construction project or transporting raw materials from a construction project, and which is operating on a highway that is not part of the interstate system and along a route of travel approved by the department or the appropriate local authority, may exceed the legal maximum weight otherwise allowed under this chapter by ten percent if the gross weight on any particular group of axles on the vehicle does not exceed the gross weight allowed under this chapter for that group of axles. If the vehicle exceeds the ten percent tolerance allowed under this subsection, the fine shall be computed on the difference between the actual weight and the ten percent tolerance weight allowed for the axle or tandem axle. 9. A vehicle or combination of vehicles transporting materials or equipment on nonprimary highways to or from a construction project or commercial plant site may operate under the maximum gross weight table for primary highways in subsection 6, paragraph “a”, or the maximum gross weight table for noninterstate highways in subsection 6, paragraph “c”. When crossing a bridge, such a vehicle or combination of vehicles shall comply with any weight restriction imposed for the bridge pursuant to section 321.471 or 321.474, provided signs that conform to the manual of uniform traffic-control devices adopted by the department that give notice of the restriction are posted as required under section 321.472 or 321.474, as applicable. 10. A vehicle designed to tow wrecked or disabled vehicles shall be exempt from the weight limitations in this section while the vehicle is towing a wrecked or disabled vehicle. 11. a. A person who operates a vehicle in violation of this section, and an owner, or any other person, employing or otherwise directing the operator of a vehicle, who requires or knowingly permits the operation of a vehicle in violation of this section shall be fined according to the following schedule: Thu Dec 11 19:42:09 2025 Iowa Code 2026, Section 321.463 (70, 3) 7 MOTOR VEHICLES AND LAW OF THE ROAD, §321.463 AXLE, TANDEM AXLE, AND GROUP OF AXLES WEIGHT VIOLATIONS Pounds Overloaded Amount of Fine Up to and including 1,000 pounds Over 1,000 pounds up to and including 2,000 pounds Over 2,000 pounds up to and including 3,000 pounds Over 3,000 pounds up to and including 4,000 pounds Over 4,000 pounds up to and including 5,000 pounds Over 5,000 pounds up to and including 6,000 pounds Over 6,000 pounds up to and including 7,000 pounds Over 7,000 pounds up to and including 8,000 pounds Over 8,000 pounds up to and including 9,000 pounds Over 9,000 pounds up to and including 10,000 pounds Over 10,000 pounds up to and including 11,000 pounds Over 11,000 pounds up to and including 12,000 pounds Over 12,000 pounds up to and including 13,000 pounds Over 13,000 pounds up to and including 14,000 pounds Over 14,000 pounds up to and including 15,000 pounds Over 15,000 pounds up to and including 16,000 pounds Over 16,000 pounds up to and including 17,000 pounds Over 17,000 pounds up to and including 18,000 pounds Over 18,000 pounds up to and including 19,000 pounds Over 19,000 pounds up to and including 20,000 pounds Over 20,000 pounds $12 $22 $155 $240 $375 $585 $850 $950 $1,050 $1,150 $1,300 $1,400 $1,500 $1,600 $1,700 $1,800 $1,900 $2,000 $2,100 $2,200 $2,200 plus ten cents per pound in excess of 20,000 pounds b. Fines for gross weight violations for vehicles or combinations of vehicles shall be assessed at one-half of the fine rate schedule for axle, tandem axle, and groups of axles weight violations. c. Except as otherwise provided, the amount of the fine to be assessed shall be computed on the difference between the actual weight and the maximum legal weight specified in this section. d. The schedule of fines may be assessed in addition to any other penalties provided for in this chapter. 12. Overloads on axles and tandem axles and overloads on groups of axles or on an entire Thu Dec 11 19:42:09 2025 Iowa Code 2026, Section 321.463 (70, 3) §321.463, MOTOR VEHICLES AND LAW OF THE ROAD 8 vehicle or combination of vehicles shall be considered as separate violations of the provisions of this section. 13. A person shall not issue or execute, or cause to be issued or executed, a bill of lading, manifest, or shipping document of any kind which states a false weight of the cargo set forth on such bill, manifest, or document, which is less than the actual weight of the cargo. 14. a. A person operating a vehicle or combination of vehicles equipped with a retractable axle may raise the axle when necessary to negotiate a turn, provided that the retractable axle is lowered within one thousand feet following completion of the turn. This paragraph does not apply to a vehicle or combination of vehicles operated on an interstate highway, including a ramp to or from an interstate highway, or on a bridge. b. A vehicle or combination of vehicles operated with a retractable axle raised as permitted under paragraph “a” is exempt from the weight limitations of this section as long as the vehicle or combination of vehicles is in compliance with the weight limitations of this section when the retractable axle is lowered. c. This subsection does not prohibit the operation of a vehicle or combination of vehicles equipped with a retractable axle with the retractable axle raised when the vehicle or combination of vehicles is in compliance with the weight limitations of this section with the retractable axle raised. 15. A person who violates this section commits a simple misdemeanor. [C24, 27, 31, 35, §5065; C39, §5035.12; C46, 50, 54, 58, 62, 66, 71, 73, 75, 77, 79, 81, §321.463; 81 Acts, ch 110, §1, ch 111] 89 Acts, ch 200, §1, 2; 92 Acts, ch 1238, §35; 94 Acts, ch 1199, §79; 95 Acts, ch 118, §26; 96 Acts, ch 1089, §4; 97 Acts, ch 100, §5, 12; 97 Acts, ch 104, §22; 98 Acts, ch 1103, §2; 98 Acts, ch 1178, §6, 7; 99 Acts, ch 108, §7; 2000 Acts, ch 1016, §17; 2000 Acts, ch 1040, §1; 2001 Acts, ch 32, §23 – 25; 2002 Acts, ch 1063, §33, 55; 2005 Acts, ch 20, §5 – 7, 12, 13; 2007 Acts, ch 143, §17; 2009 Acts, ch 133, §121; 2010 Acts, ch 1139, §1; 2010 Acts, ch 1140, §16, 17; 2013 Acts, ch 27, §1; 2013 Acts, ch 140, §62; 2017 Acts, ch 29, §96; 2017 Acts, ch 149, §2; 2018 Acts, ch 1172, §73; 2019 Acts, ch 15, §1; 2019 Acts, ch 138, §3; 2019 Acts, ch 158, §1; 2020 Acts, ch 1063, §152; 2021 Acts, ch 140, §1, 4; 2023 Acts, ch 85, §17 Referred to in §312.2, 321.453, 321.457, 321.459, 321.466, 321.473, 321E.2, 321E.7, 321E.8, 321E.9, 321E.9A, 321E.16, 321E.17, 321E.26, 321E.27, 321E.29, 321E.29A, 321E.29B, 321E.30, 805.8A(12)(e) For scheduled fines listed in subsection 11, violations are charged and fines are applied pursuant to §805.8A, subsection 12, paragraph e Thu Dec 11 19:42:09 2025 Iowa Code 2026, Section 321.463 (70, 3)