Truck & Trailer Size Weight 2017 12 Illinois Limits Tolerances
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Size & Weight Limits [625 ILCS 5/15-111]
The allowable width, height and weight of trucks and
trailers operating in Illinois is based on uniform stand-
ards, but can vary by road system if restrictions are
posted. Allowable lengths vary.
Federal bridge formula allows 20,000# per single
axle, 34,000# per tandem axle, and 80,000# maximum
gross vehicle weight (GVW.)
The number of axles and their spacing determines the
allowable gross weight.
Width limit is 102 inches on all roads unless a nar-
rower restriction is posted.
Length (semi)
Class I & II routes: overall unlimited; trailer 53’
Other State Highways: overall 65’; trailer 53’
Local Class III routes: overall 65’; trailer 53’
Other Local Roads: overall 55’; length of trailer not
specified. (See “Access”)
A tandem axle is defined as any two or more single
axles whose centers are more than 40 inches and not
more than 96 inches apart (on-centers.)
The registered (licensed) weight of the vehicle also im-
poses an enforceable weight restriction.
For information on the allowable dimension and weight of
trucks and trailers operating on state and local roads in
Illinois check the IDOT website at
http://www.idot.illinois.gov/assets/uploads/files/idot-forms/
oper/oper%20753.pdf
License Plates
Single trucks must be registered (licensed) to cover the
gross weight of vehicle and its load.
When trucks and trailers are used in combination, it is not
necessary to have the license plate on each vehicle cover
the weight carried by that individual vehicle. Illinois’
“marriage of licenses” provision means that when two li-
censed vehicles are used in combination, the sum of their
licensed weights must meet or exceed the sum of their
gross weights. [625 ILCS 5/3-401(c-1)(3)]
Designated Routes
There are three classes of designated routes:
Class I – Interstate-type routes, allows some vehicles
longer than on Class II routes;
Class II – Generally, major state highways,
allows some vehicles longer than on Class III or on
non-designated routes;
Class III – [Local roads only] Allows longer combina-
tion vehicles than otherwise allowed.
The “Class III” designation is no longer used on State
routes, but local jurisdictions may choose to. For that lo-
cal designation to be effective, signs must be posted
showing the route to be Class II or Class III.
Scale Program
The Illinois State Police and IDOT jointly operate semi-
portable scales among 21 state police districts.
Many state troopers carry portable (“pancake” or
“wheel load weigher”) scales in their squad cars.
There are approximately 32 permanent scale sites op-
erated by the State of Illinois.
An IDOT team is generally assigned to a state police
district for five days per week and assists officers by
setting up the scale. The officer-in-charge determines
a scale's location, and the police enforce weight regu-
lations, not IDOT staff.
IDOT’s portable and semi-portable scales are
re-calibrated by IDOA two times each year – twice as
often as required of commercial scales.
SIZE & WEIGHT LIMITS FOR ILLINOIS FARMERS
ON THE ROAD
All roads in Illinois have standardized weight limits based on what is called the Federal Bridge Formula. That
formula establishes both a gross weight limit and an axle weight limit for roads and bridges. The formula varies
the allowable gross weight based on axle spacing. But allowable weights can also be influenced by reduced
weight limit postings, license plate limits, manufacturers’ weight ratings of equipment, and more. Allowable
dimensions of vehicles, too, are generally restricted and must be heeded when on public roads.
Tolerance [625 ILCS 5/15-112(e)]
State law provides a “tolerance” for vehicle overweight
to accommodate uncertainties in loading.
Vehicles registered for 73,280# or less are allowed a
2,000# tolerance for axle weight and a 2,000# toler-
ance for gross weight.
Vehicles registered for more than 73,280# are allowed
a 2,000# tolerance for axle weight but only 1,000# for
gross weight. The gross weight tolerance jumps to
2,000# when weighed on portable scales.
Tolerance does not apply to the registered (licensed)
weight of the vehicle.
If overweight but within the tolerance, the vehicle must
be parked so the weight can be shifted or removed.
Once within legal limits, the vehicle will be allowed to
proceed and no overweight ticket will be issued.
Drivers' Rights
A police officer checking a truck's weight may direct
the driver to the nearest available scale certified by the
Illinois Department of Agriculture. [625 ILCS 5/15-112]
State Police generally favor using state-owned scales.
The driver may request, but not demand, an alternate
location.
Portable and semi-portable scales should be placed in
a location that does not present a traffic hazard and
that is relatively level and firm. Up to a 3%
grade is generally within the scale’s toler-
ance but in no case should the vehicle roll
due to the slope of the scale.
The vehicle’s brakes should not be applied
and no on-board mixing equipment should
be operating while being weighed.
Accumulations of mud, snow and ice gen-
erally may be removed from the outside of
the vehicle before it is weighed, but not
once on the scale.
Fines [625 ILCS 5/15-113]
When police issue an overweight citation, the driver
generally will not be allowed to move the vehicle until
bond is posted in the amount of the fine (perishable
loads may be excepted.)
The circuit clerk in each county usually determines the
form of acceptable bond. Most accept some form of
certified check or money order, but not all accept per-
sonal checks or even cash.
Generally, fines start at about $70 per 500# overweight
for lesser violations and incrementally increase. For
overweight violations of 5,001# or more, the fine is
$1,500 plus $150 for each additional 500# or portion
thereof.
These fines are double what they were prior to 2010.
Permits [625 ILCS 5/15-301]
All permits for overweight or over-dimension should be
obtained in writing.
Each road jurisdiction issues its own permits – no juris-
diction may issue permits for another without prior in-
tergovernmental agreement.
Overweight permits for gross weights are generally
available only for “non-divisible” loads, (i.e.: large equip-
ment or construction components than cannot readily be
disassembled.) State law generally does not allow road
officials to issue permits for “divisible” loads such as
grain or livestock, except under a Harvest Season
Emergency.
Overweight axle permits are available to farmers oper-
ating trucks hauling grain, livestock, fruits and vegeta-
bles, or ensilage. This allows the axle(s) to exceed
standard weight limits by:
2-axle truck = 35%
3-axle truck = 20%
4-axle truck = 20%
5-axle truck = 10%
It does not allow additional gross weight and it does
not allow weights in excess of the registered
(licensed) weight. This permit is not available for Inter-
state highways. [625 ILCS 5/15-301(e)]
The State’s permit form for hauling ag prod-
ucts is available at:
https://truckpermits.dot.illinois.gov/. All over-
size/overweight permits from IDOT must be
applied for electronically.
Each local jurisdiction will supply its’ own
form. A sample form for townships’ Axle
Overweight Permit is available on the Town-
ship Officials of Illinois website at:
http://www.toi.org/Resources/Download-
Center.aspx
Not all townships will use this form—check locally.
Harvest Season Emergency (HSE) Permit. This per-
mit is available only in those years in which the Gover-
nor declares a HSE. See pages 21-22 for details.
Don’t
overlaod . . .
save your
road.
Maximum load in pounds carried on any
group of 2 or more consecutive axles
Feet 2 axles 3 axles 4 axles 5 axles 6 axles
4 34,000
5 34,000
6 34,000
7 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
25 54,500 58,500 63,500 69,000
26 55,500 59,500 64,000 69,500
27 56,000 60,000 65,000 70,000
28 57,000 60,500 65,500 71,000
29 57,500 61,500 66,000 71,500
30 58,500 62,000 66,500 72,000
31 59,000 62,500 67,500 72,500
32 60,000 63,500 68,000 73,000
33 64,000 68,500 74,000
34 64,500 69,000 74,500
35
65,500 70,000 75,000
36 66,000 70,500 75,500
37 66,500 71,000 76,000
38 67,500 72,000 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
Distance
Between
Axles
Measured to the nearest foot between the extremes of any group of two or
more consecutive axles.
Gross weights for 5 and 6 axles applicable only to a combination of vehicles.
Two consecutive sets of tandems may carry 34,000 pounds each providing
the overall distance between the first and last axles of such consecutive sets of
tandems is 36 feet or more.
If the distance between 2 axles is 96 inches or less, the 2 axles are tandem
axles and the maximum total weight may not exceed 34,000 pounds, notwithstand-
ing the higher limit resulting from the application of the formula.
If the distance between the centers of the first and third axles is a group of
consecutive axles does not exceed 96 inches, the group is a tandem.
Maximum single axle 20,000 pounds; maximum tandem 34,000 pounds.
Combinations of vehicles designated as special haul vehicles which include a
semitrailer manufactured prior to the model year 2004 and first registered in Illinois
prior to January 1, 2005 having five axles with a distance of 42 feet or less be-
tween extremes may have a gross weight of 72,000 pounds provided the weight
shall not exceed 18,000 pounds on a single axle of 32,000 pounds on a tandem.
For such combinations manufactured subsequent to September 9, 1986, the mini-
mum distance between the first and last axles of the two sets of tandems must be
18 feet 6 inches or more.
Exception
Maximum loading for typical vehicles
Vehicle or Combination Maximum Weight — Pounds
Federal Bridge Formula in Illinois
Axle 1 20,000
Axle 2 20,000
Axles 1, 2 40,000
Axle 1 20,000
Axles 2, 3 34,000
Axles 1, 2, 3 54,000
Axle 1 20,000
Axles 2 20,000
Axles 3, 4 34,000
Axles 1, 2 40,000
Axles 2, 3, 4 54,000
Axles 1, 2, 3, 4 66,000
Axle 1 20,000
Axles 2, 3 34,000
Axles 4, 5 34,000
Axles 1, 2, 3 50,000
Axles 2, 3, 4, 5 68,000
Axles 1, 2, 3, 4, 5 80,000
Axle 1 20,000
Axles 2, 3 34,000
Axles 4, 5, 6 42,500
Axles 1, 2, 3 48,000
Axles 2, 3, 4, 5, 6 67,500
Axles 1, 2, 3, 4, 5, 6 80,000
24’
18’
31’
43’
16’
36’
19’
51’
36’
24’ 12’
A pdf version of this
document is available
with hyperlinks at the
ilfb web address.
Copyright 2017 © Illinois Farm Bureau®
Revised 2018-02
Type of
Highway
or Street
Maximum Legal Dimensions
A B C D E F G H I J K
Class I 8’-6” 13’-6” 42’ N.S. 53’ 45’-6” N.S. N.S. 28’-6” N.S. 60’
Class II 8’-6” 13’-6” 42’ N.S. 53’ 45’-6” N.S. N.S. 28’-6” 65’ 60’
Other State
Highways 8’-6” 13’-6” 42’ 65’ 53’ 42’-6” 55’ 60’ N.S. N.S. 60’
Class III 8’-6” 13’-6” 42’ 65’ 53’ 42’-6” 55’ 60’ N.S. N.S. 60’
Other Local Roads
& Streets 8’-6” 13’-6” 42’ 65’ N.S. 42'-6" N.S. 60’ N.S. N.S. 60’
C
A
B
All
Trucks
Width & Height Length, Single Vehicle
G
Length, Truck-Tractor/Semi-Trailer
D
E
F
Kingpin
J
H
I I
Length, Truck-Tractor/Semi-Trailer (Double Bottom) Length, All Other Combinations
K
65 feet overall (bumper-to-
bumper) and/or 55 feet from
center of front axle to center of
rear axle.
Applies on semi-trailers
longer than 48 feet.
Tandem is defined as any
2 or more single axles whose
centers are more than 40
inches and not more than 96
inches apart, measured to the
nearest inch between extreme
axles.
Maximum legal dimensions of motor vehicles
This document
prepared and
provided by: www.ilfb.org
More Information
• Illinois Farm Bureau® [General Info]
309-557-3274
http://www.ilfb.org
• Illinois State Police [Enforcement]
217-782-6267
http://www.isp.state.il.us/
• Illinois Department of Transportation
[Weights, Permits & Routes]
217-782-6271
hps://truckpermits.dot.illinois.gov/
• Secretary of State [License Plates]
217-785-1801
http://www.cyberdriveillinois.com/publications/
motoristpub.html#comfarmtruck
Farm Equipment
Implements of husbandry generally enjoy an exemption from most
weight limits in Illinois. However, farm wagons are limited to 36,000
pounds GVW. There is no weight restriction on axles and it mat-
ters not how many axles the wagon has—the
gross weight limit remains at 36,000 pounds.
That 36,000 pound
GVW restriction also
applies to: fertilizer
buggies, sprayers, au- ger wagons, liquid
manure wagons, liquid fertilizer carts, NH3 nurse tanks (also limited to
3,000 gallons capacity), water wagons, and virtually any other cargo-
type farm implement.
Farm wagons are
limited to a
maximum GVW of
36,000#
40”
96”
Tandem Axle
Single Axle
Maximum Weight
20,000#
Tandem Axle
Maximum Weight
34,000#
