Federal & State Regulations | Size/Weight limits - Idaho

Dimension	National Network	State and Other Supplemental Highways
Width:	8' 6"	8' 6"
Height:	14'	14'
Length:	National Network	State and Other Supplemental Highways
Bus
Articulated bus
Straight Trucks	45'	45'
Straight truck and trailer	75'	75'
Tractor-semitrailer combinations	75' unless otherwise noted	75' unless otherwise noted
Semitrailer	53'	48'
Tractor-twin-trailer combination	68' of trailers including tongues	61' of trailers including tongues or 75' overall
Trailers of twin-trailer combinations	68' of trailers including tongues	61' of trailers including tongues or 75' overall
Boat-transporter combination	65'	65'
Overhang limitations	front 3', rear 4'	front 3', rear 4'
Stinger-steered boat-transporter	75'	75'
Overhang limitations	front 3', rear 4'	front 3', rear 4'
Auto-transporter	65'	65'
Overhang limitations	front 4', rear 6'	front 4', rear 6'
Stinger-steered auto-transporter	80'	80'
Overhang limitations	front 4', rear 6'	front 4', rear 6'
Saddlemount	97'	75'
General overhang limitations	4' front, 10' rear	4' front, 10' rear
Drawbar
Dromedary
Kingpin to rearaxle
Length special limitations or restrictions	1-mile access to terminals or facilities for fuel, food, lodging, or repairs.
Weight:	Interstate and Defense Highways	State and Other Supplemental Highways
Steer axle	20,000 or manufacturer’s rating of tire/axle	20,000 or manufacturer’s rating of tire/axle
Single axle	20,000 or manufacturer’s rating of tire/axle	20,000 or manufacturer’s rating of tire/axle
Tandem axle	34,000	34,000
Tridem axle	42,000	42,000
Gross vehicle weight	80,000 Up to 129,000 lbs if registration covers - permits available	80,000 Up to 129,000 lbs if registration covers - permits available
Load per inch width of tire	600 of tire width or the manufacturer’s load rating, whichever is less	600 of tire width or the manufacturer’s load rating, whichever is less
Per wheel
Tolerances
APU allowance
Natural gas allowance
Weight special limitations or restrictions	Farm vehicles, vehicles that are operated to transport forest products, and refuse or sanitation trucks that are operated by a city, county or state agency, or by a designated agent of the agency to transport refuse may operate up to 2,000 pounds in excess of any axle, bridge formula, or gross weight limit. This operation cannot be part of the federal-aid interstate system, or exceed a posted bridge weight or other seasonal or temporary weight limit posting.

Farm vehicles, vehicles that are operated to transport forest products, and refuse or sanitation trucks that are operated by a city, county or state agency, or by a designated agent of the agency to transport refuse may operate up to 2,000 pounds in excess of any axle, bridge formula, or gross weight limit. This operation cannot be part of the federal-aid interstate system, or exceed a posted bridge weight or other seasonal or temporary weight limit posting.

	Column A	Column B		Column A	Column B
Distance in feet between first and last axle of any group of consecutive axles	Vehicles with three or four axles	Vehicles with five or more axles	Distance in feet between first and last axle of any group of consecutive axles	Vehicles with three or four axles	Vehicles with five or more axles
Single Axle Weight	20,000	20,000	28	66,000	70,950
3 thru 12	37,800	37,800	29	66,000	71,500
13	56,470	56,470	30	66,000	72,050
14	57,940	57,940	31		72,600
15	59,400	59,400	32		73,150
16	60,610	60,610	33		73,700
17	61,820	61,820	34		74,250
18	63,140	63,140	35		74,800
19	64,350	64,350	36		75,350
20	65,450	65,450	37		75,900
21	66,000	66,330	38		76,450
22	66,000	67,250	39		77,000
23	66,000	67,880	40		77,550
24	66,000	68,510	41		78,100
25	66,000	69,150	42		78,650
26	66,000	69,770	43+		79,000
27	66,000	70,400

Distance in feet between first and last axle of any group of consecutive axles	Excess Weight Permits on Interstate Highways if Over 80,000 lbs
	Column C 2 axles	Column D 3 axles	Column E 4 axles	Column F 5 axles	Column G 6 axles	Column H 7 axles	Column I 8 axles	Column J 9 axles
Single Axle Weight	20,000	20,000	20,000	20,000	20,000	20,000	20,000	20,000
4	34,000
5	34,000
6	34,000
7	34,000
8	34,000
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		47,000	52,000
16		48,000	52,500	58,000
17		48,500	53,500	58,500
18		49,500	54,000	59,000
19		50,000	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	82,000
29		57,500	61,500	66,000	71,500	77,000	82,500
30		58,500	62,000	66,500	72,000	77,500	83,000
31		59,000	62,500	67,500	72,500	78,000	83,500
32		60,000	63,500	68,000	73,000	78,500	84,500	90,000
33			64,000	68,500	74,000	79,000	85,000	90,500
34			64,500	69,000	74,500	80,000	85,500	91,000
35			65,500	70,000	75,000	80,500	86,000	91,500
36			68,000	70,500	75,500	81,000	86,500	92,000
37			68,000	71,000	76,000	81,500	87,000	93,000
38		[Note 1]	68,000	71,500	77,000	82,000	87,500	93,500
39			68,000	72,500	77,500	82,500	88,500	94,000
40			68,500	73,000	78,000	83,500	89,000	94,500
41			69,500	73,500	78,500	84,000	89,500	95,000
42			70,000	74,000	79,000	84,500	90,000	95,500
43			70,500	75,000	80,000	85,000	90,500	96,000
44			71,500	75,500	80,500	85,500	91,000	96,500
45			72,000	76,000	81,000	86,000	91,500	97,500
46			72,500	76,500	81,500	87,000	92,500	98,000
47			73,500	77,500	82,000	87,500	93,000	98,500
48			74,000	78,000	83,000	88,000	93,500	99,000
49			74,500	78,500	83,500	88,500	94,000	99,500
50			75,500	79,000	84,000	89,000	94,500	100,000
51			76,000	80,000	84,500	89,500	95,000	100,500
52			76,500	80,500	85,000	90,500	95,500	101,000
53			77,500	81,000	86,000	91,000	96,500	102,000
54			78,000	81,500	86,500	91,500	97,000	102,500
55			78,500	82,500	87,000	92,000	97,500	103,000
56			79,500	83,000	87,500	92,500	98,000	103,500
57		[Note 2]	80,000	83,500	88,000	93,000	98,500	104,000
58				84,000	89,000	94,000	99,000	104,500
59				85,000	89,500	94,500	99,500	105,000
60				85,500	90,000	95,000	100,500	105,500
61				86,000	90,500	95,500	101,000	105,500
62				87,000	91,000	96,000	101,500	105,500
63				87,500	92,000	96,500	102,000	105,500
64				88,000	92,500	97,500	102,500	105,500
65				88,500	93,000	98,000	103,000	105,500
66				89,500	93,500	98,500	103,500	105,500
67				90,000	94,000	99,000	104,500	105,500
68				90,500	95,000	99,500	105,000	105,500
69				91,000	95,500	100,000	105,500	105,500
70				92,000	96,000	101,000	105,500	105,500
71				92,500	96,500	101,500	105,500	105,500
72				93,000	97,000	102,000	105,500	105,500
73				93,500	98,000	102,500	105,500	105,500
74				94,500	98,500	103,000	105,500	105,500
75				95,000	99,000	103,500	105,500	105,500
76				95,500	99,500	104,500	105,500	105,500
77				96,000	100,000	105,000	105,500	105,500
78				97,000	101,000	105,500	105,500	105,500
79				97,500	101,500	105,500	105,500	105,500
80				98,000	102,000	105,500	105,500	105,500
81				98,500	102,500	105,500	105,500	105,500
82				99,000	103,000	105,500	105,500	105,500
83				100,000	104,000	105,500	105,500	105,500
84					104,500	105,500	105,500	105,500
85					105,000	105,500	105,500	105,500
86 or more					105,500	105,500	105,500	105,500

Note 1:	An exception to the formula which computes the weight limits of Columns C through J provides that axle groups consisting of two tandems in an overall spacing of 36 feet may have a total loading of 68,000 pounds; 34,000 pounds per tandem.
Note 2:	The extra length vehicle combination must be registered for the maximum gross weight when exceeding 80,000 pounds and must purchase an annual excess weight permit. When calculating legal weight limits, the distance between axles shall be measured to the nearest foot. When a fraction is exactly ¹/₂ foot, the next larger whole number shall be used.

	Column K	Column L		Column K	Column L
Distance in feet between first and last axle of any group of consecutive axles	Vehicles with Three or Four Axles	Vehicles with Five or more Axles	Distance in feet between first and last axle of any group of consecutive axles	Vehicles with Three or Four Axles	Vehicles with Five or more Axles
Single Axle Weight	20,000	20,000	28	66,000	70,950
3 thru 12	37,800	37,800	29	66,000	71,500
13	56,470	56,470	30	66,000	72,050
14	57,940	57,940	31		72,600
15	59,400	59,400	32		73,150
16	60,610	60,610	33		73,700
17	61,820	61,820	34		74,250
18	63,140	63,140	35		74,800
19	64,350	64,350	36		75,350
20	65,450	65,450	37		75,900
21	66,000	66,330	38		76,450
22	66,000	67,250	39		77,000
23	66,000	67,880	40		77,550
24	66,000	68,510	41		78,100
25	66,000	69,150	42		78,650
26	66,000	69,770	43+		80,000
27	66,000	70,400

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Size/Weight limits - Idaho

Bridge rules

Weight Limits on Interstate System routes for Special Products*

Weight Limits for Loads exceeding 79,000 pounds on Interstate & 80,000 pounds on non-Interstate routes

Weight Limits, up to 80,000 pounds for all commodities on non-interstate system routes