Sec. 1. (a) Except as provided in subsections (b) and (c), a person may not operate or cause to be operated upon a highway a vehicle or combination of vehicles having weight in excess of one (1) or more of the following limitations:

(1) The total gross weight, with load, in pounds of any vehicle or combination of vehicles may not exceed an overall gross weight on a group of two (2) or more consecutive axles produced by application of the following formula:

W = 500 { [(LN) ÷ (N-1)] + 12N + 36 }

where W equals the overall gross weight on any group of two (2) or more consecutive axles to the nearest five hundred (500) pounds, L equals the distance in feet between the extreme of any group of two (2) or more consecutive axles, and N equals the number of axles in the group under consideration, except that two (2) consecutive sets of tandem axles may carry a gross load of thirty-four thousand (34,000) pounds each, providing the overall distance between the first and last axles of the consecutive sets of tandem axles is thirty-six (36) feet or more. The overall gross weight limit, calculated under this subdivision, may not exceed eighty thousand (80,000) pounds.

(2) The weight concentrated on the roadway surface from any tandem axle group may not exceed the following:

(A) Thirty-four thousand (34,000) pounds total weight.

(B) Twenty thousand (20,000) pounds on an individual axle in a tandem group.

(3) A vehicle may not have a maximum wheel weight, unladen or with load, in excess of eight hundred (800) pounds per inch width of tire, measured between the flanges of the rim or an axle weight in excess of twenty thousand (20,000) pounds.

(b) The enforcement of weight limits under this section is subject to the following:

(1) It is lawful to operate within the scope of a permit, under weight limitations established by the Indiana department of transportation and in effect on July 1, 1956, as provided in IC 9-20-6.

(2) It is lawful to operate or cause to be operated a vehicle or combination of vehicles on a heavy duty highway or an extra heavy duty highway designated by the Indiana department of transportation if operated within the imposed limitations.

(3) Subsection (a) does not apply to any highway, road, street, or bridge for which a lesser weight limit is imposed by local authorities under IC 9-20-1-3 or IC 9-20-7-2. However, the local authority may by appropriate action establish and designate a county or city highway, road, or street or part of a highway, road, or street as a heavy duty highway subject to the weight limitations established under IC 9-20-5.

(4) Vehicles operated on toll road facilities are subject to rules of weight adopted for toll road facilities by the Indiana department of transportation under IC 8-15-2 and are not subject to subsection (a) when operated on a toll road facility.

(5) For purposes of a heavy duty vehicle that is equipped with an auxiliary power unit, the weight limitations provided in subsection (a) are increased by four hundred (400) pounds.

(6) For purposes of a vehicle that uses natural gas as a motor fuel, the weight limitations provided in subsection (a) are increased by two thousand (2,000) pounds.

(c) The greater of the weight limits imposed under subsection (a) or this subsection applies to vehicles operated upon a highway. The weight limits in effect on January 4, 1975, for any highway that is not designated as a heavy duty highway under IC 9-20-5 are the following:

(1) The total gross weight, with load, in pounds of a vehicle or combination of vehicles may not exceed seventy-three thousand two hundred eighty (73,280) pounds.

(2) The total weight concentrated on the roadway surface from a tandem axle group may not exceed sixteen thousand (16,000) pounds for each axle of a tandem assembly.

(3) A vehicle may not have a maximum wheel weight, unladen or with load, in excess of eight hundred (800) pounds per inch width of tire, measured between the flanges of the rim, or an axle weight greater than eighteen thousand (18,000) pounds.

(d) For purposes of this section, "auxiliary power unit" means an integrated system that:

(1) provides heat, air conditioning, engine warming, or electricity to components on a heavy duty vehicle; and

(2) is certified by the administrator of the United States Environmental Protection Agency under 40 CFR 89 as meeting applicable emission standards.

(e) For purposes of this section, "heavy duty vehicle" means a vehicle that:

(1) has a gross vehicle weight rating greater than eight thousand five hundred (8,500) pounds; and

(2) is powered by a diesel engine.

[Pre-1991 Recodification Citation: 9-8-1-12(a); (b); (c); Pre-2016 Revision Citations: subsection (d) formerly 9-13-2-10.2; subsection (e) formerly 9-13-2-72.5.]

As added by P.L.2-1991, SEC.8. Amended by P.L.65-2010, SEC.3; P.L.277-2013, SEC.16; P.L.5-2015, SEC.25; P.L.198-2016, SEC.339.