Federal & State Regulations | Size/Weight limits - Iowa

Dimension	National Network	State and Other Supplemental Highways
Width:	8' 6" 12' 5" for certain agricultural commodities	8' 6" 12' 5" for certain agricultural commodities
Height:	13' 6" 14' for auto transporters 14' 6" for certain agricultural commodities	13' 6" 14' for auto transporters 14' 6" for certain agricultural commodities
Length:	National Network	All Highways
Bus	45'	45'
Articulated bus	61'	61'
Straight Trucks	45'	45'
Straight truck and trailer	65'	65'
Tractor-semitrailer combinations	No limit with legal trailer	No limit with legal trailer
Semitrailer	53' 57' lowboy trailers allowed for the transport of construction equipment in a tractor semitrailer combination	53' 57' lowboy trailers allowed for the transport of construction equipment in a tractor semitrailer combination
Tractor-twin-trailer combination	No limit with legal trailer	No limit with legal trailer
Trailers of twin-trailer combinations	28' 6"	28' 6"
Boat-transporter combination	65'	65'
Overhang limitations	3' front, 4' rear	3' front, 4' rear
Stinger-steered boat-transporter
Overhang limitations
Auto-transporter	65'	65'
Overhang limitations	3' front, 4' rear	3' front, 4' rear
Stinger-steered auto-transporter	80'	80'
Overhang limitations	4' front, 6' rear	4' front, 6' rear
Saddlemount	97'	97'
General overhang limitations
Drawbar	15' conditional	15' conditional
Dromedary
Kingpin to rearaxle
Length special limitations or restrictions
Weight:	Interstate and Defense Highways	All Highways
Steer axle	20,000 to tire load rating or 600 lb per inch	20,000 to tire load rating or 600 lb per inch
Single axle	20,000	20,000
Tandem axle	34,000	34,000
Tridem axle	42,000 with minimum 8' 1" spacing	42,000 with minimum 8' 1" spacing
Gross vehicle weight	80,000	80,000
Load per inch width of tire	575 or tire rating	575 or tire rating
Per wheel	NS manufacturer’s sidewall weight rating	NS manufacturer’s sidewall weight rating
Tolerances
APU allowance	550	550
Natural gas allowance	2,000	2,000
Weight special limitations or restrictions

Spread Axle Livestock Transports — 5-axle livestock transportation trucks with a spread axle trailer are allowed to carry a gross weight of 86,000 lb under the following conditions:

Travel over 80,000-lb gross weight is not allowed on the Interstate highway system. This law applies to only the non-interstate highway system.
The truck/trailer must have at least 61 ft of overall wheelbase.
The trailer spread-axles must have at least 8 ft 1 in. of spacing.
You may only transport livestock on the vehicle.
You are not allowed to exceed posted bridge or roadway embargoes.

Bridge rules

FEDERAL BRIDGE FORMULA:The maximum weight of any vehicle or combination of vehicles and load may not exceed that which is determined by the following formula:

Primary Highway System - Interstate Highway System, and Non-Interstate Federal and State Highways; Maximum Legal Tandem, Group and Gross Weights

Distance* in feet	2 axles	3 axles	4 axles	5 axles	6 axles	7 axles
4	34,000	34,000
5	34,000	34,000
6	34,000	34,000
7	34,000	34,000
8′ 1″	38,000	42,000
9	39,000	42,500
10	40,000	43,500	48,500
11	40,000	44,000	49,500
12	40,000	45,000	50,000
13	40,000	45,500	50,500	56,000
14	40,000	46,500	51,500	57,000
15	40,000	47,000	52,000	57,500
16	40,000	48,000	52,500	58,000
17	40,000	48,500	53,500	58,500	64,000
18	40,000	49,500	54,000	59,000	65,000
19	40,000	50,000	54,500	60,000	65,500
20	40,000	51,000	55,500	60,500	66,000	71,500
21	40,000	51,500	56,000	61,000	66,500	72,500
22	40,000	52,500	56,500	61,500	67,000	73,000
23	40,000	53,000	57,500	62,500	68,000	73,500
24	40,000	54,000	58,000	63,000	68,500	74,000
25	40,000	54,500	58,500	63,500	69,000	74,500
26	40,000	55,500	59,500	64,000	69,500	75,000
27	40,000	56,000	60,000	65,000	70,000	76,000
28	40,000	57,000	60,500	65,500	71,000	76,500
29	40,000	57,500	61,500	66,000	71,500	77,000
30	40,000	58,500	62,000	66,500	72,000	77,500
31	40,000	59,000	62,500	67,500	72,500	78,000
32	40,000	60,000	63,500	68,000	73,000	78,500
33	40,000	60,000	64,000	68,500	74,000	79,500
34	40,000	60,000	64,500	69,500	74,500	80,000
35	40,000	60,000	65,500	70,000	75,000	80,000
36	40,000	60,000	68,000	70,500	75,500	80,000
37	40,000	60,000	68,000	71,000	76,000	80,000
38	40,000	60,000	68,000	72,000	77,000	80,000
39	40,000	60,000	68,000	72,500	77,500	80,000
40	40,000	60,000	68,500	73,000	78,000	80,000
41	40,000	60,000	69,500	73,500	78,500	80,000
42	40,000	60,000	70,000	74,000	79,000	80,000
43	40,000	60,000	70,500	75,000	80,000	80,000
44	40,000	60,000	71,500	75,500	80,000	80,000
45	40,000	60,000	72,000	76,000	80,000	80,000
46	40,000	60,000	72,500	76,500	80,000	80,000
47	40,000	60,000	73,500	77,500	80,000	80,000
48	40,000	60,000	74,000	78,000	80,000	80,000
49	40,000	60,000	74,500	78,500	80,000	80,000
50	40,000	60,000	75,500	79,000	80,000	80,000
51	40,000	60,000	76,000	80,000	80,000	80,000
52	40,000	60,000	76,500	80,000	80,000	80,000
53	40,000	60,000	77,500	80,000	80,000	80,000
54	40,000	60,000	78,000	80,000	80,000	80,000
55	40,000	60,000	78,500	80,000	80,000	80,000
56	40,000	60,000	79,500	80,000	80,000	80,000
57	40,000	60,000	80,000	80,000	80,000	80,000
*Measured between the centers of the extreme axles of any group of axles and rounded to the nearest whole foot.

Non-Primary Highway System - County and City Roads; Maximum Legal Tandem, Group and Gross Weights

Distance* In Feet	2 axles	3 axles	4 axles	5 axles	6 axles	7 axles
4	34,000	34,000
5	34,000	34,000
6	34,000	34,000			6- and 7-axle commercial vehicles may also use the table below.
7	34,000	34,000
8 ft 1 in.	38,000	42,000
9	39,000	42,500
10	40,000	43,500	45,000
11	40,000	44,000	46,000
12	40,000	45,000	47,000
13	40,000	45,500	48,000	48,500
14	40,000	46,500	49,000	49,500
15	40,000	47,000	50,000	50,500
16	40,000	48,000	51,000	51,500
17	40,000	48,500	52,000	52,500	54,000
18	40,000	49,500	53,000	53,500	55,000
19	40,000	50,000	54,500	54,500	56,000
20	40,000	51,000	55,500	55,500	57,000
21	40,000	51,500	56,000	56,500	58,000
22	40,000	52,500	56,500	57,500	59,000
23	40,000	53,000	57,500	58,500	60,000
24	40,000	54,000	58,000	59,500	61,000
25	40,000	54,500	58,500	60,500	62,000
26	40,000	55,500	59,500	61,500	63,000
27	40,000	56,000	60,000	62,500	64,000
28	40,000	57,000	60,500	63,500	65,000
29	40,000	57,500	61,500	64,500	66,000
30	40,000	58,500	62,000	65,500	67,000
31	40,000	59,000	62,500	66,500	68,000
32	40,000	60,000	63,500	67,500	69,000
33	40,000	60,000	64,000	68,500	70,000
34	40,000	60,000	64,500	69,500	71,000
35	40,000	60,000	65,500	70,000	72,000
36	40,000	60,000	68,000	70,500	73,000
37	40,000	60,000	68,000	71,000	74,000
38	40,000	60,000	68,000	72,000	75,000
39	40,000	60,000	68,000	72,500	76,000
40	40,000	60,000	68,500	73,000	77,000
41	40,000	60,000	69,500	73,500	78,000	78,000
42	40,000	60,000	70,000	74,000	79,000	79,000
43	40,000	60,000	70,500	75,000	80,000	80,000
44	40,000	60,000	71,500	75,500	80,000	80,000
45	40,000	60,000	72,000	76,000	80,000	80,000
46	40,000	60,000	72,500	76,500	80,000	80,000
47	40,000	60,000	73,500	77,500	80,000	80,000
48	40,000	60,000	74,000	78,000	80,000	80,000
49	40,000	60,000	74,500	78,500	80,000	80,000
50	40,000	60,000	75,500	79,000	80,000	80,000
51	40,000	60,000	76,000	80,000	80,000	80,000
52	40,000	60,000	76,500	80,000	80,000	80,000
53	40,000	60,000	77,500	80,000	80,000	80,000
54	40,000	60,000	78,000	80,000	80,000	80,000
55	40,000	60,000	78,500	80,000	80,000	80,000
56	40,000	60,000	79,500	80,000	80,000	80,000
57	40,000	60,000	80,000	80,000	80,000	80,000
*Measured between the centers of the extreme axles of any group of axles and rounded to the nearest whole foot.

The maximum gross weight for 6- and 7-axle commercial motor vehicles operated by a person with the appropriate class of CDL (or exempt from a CDL by Iowa Code 321.176A), operated on non-interstate highways:

Noninterstate Highways Maximum Gross Weight Table, 6- and 7-Axle Commercial Motor Vehicles

Distance in feet	6 axles	7 axles
44	80,500	80,500
45	81,000	81,500
46	81,500	82,500
47	82,000	83,500
4	83,000	84,000
49	83,500	85,000
50	84,000	86,000
51	84,500	87,000
52	85,000	88,000
53	86,000	88,500
54	86,500	89,500
55	87,000	90,500
56	87,500	91,500
57	88,000	92,000
58	89,000	93,000
59	89,500	94,000
60	90,000	95,000
61		95,500
62		96,000

This table does not apply to vehicles operating on the Interstate highway system or to special farm plated trucks operating on any roadway.

An indivisible load must comply with legal dimension and weight limits or be operated under the provisions of an oversize load permit.

View agency contact information.

['Size and Weight Limits']

['Sizes and weights']

...

Size/Weight limits - Iowa

Bridge rules