Illinois oversize permit requirements
Illinois grades its travel hours by the size of the load rather than applying one window to everything, and the grading is fine enough to be worth reading properly. Within twelve feet wide, thirteen feet six high and two hundred feet long, a load runs around the clock with one civilian escort in darkness. Within fourteen feet six wide and fifteen feet high, it runs daylight, seven days a week. Beyond that it loses the weekend: daylight Monday to Friday plus Saturday morning until noon.
The Chicago collar is the other constraint. Loads between fourteen feet six and sixteen feet wide are confined to a nine-to-three window on weekdays across nine counties — Cook, DuPage, Lake, Kane, Madison, McHenry, Monroe, St. Clair and Will — and the Cook County expressways cap oversize traffic at twelve feet wide, thirteen feet six high and a hundred and twenty thousand pounds regardless of permit.
Two exemptions repay knowing. Structural loads — beams, poles, pipe and culverts — travel to eighty feet in daytime, Monday to Friday, with no permit at all. Farm implements need no permit if the only thing oversize about them is width, provided they move in daylight. The permit itself runs five days, and the holiday ban starts at noon the day before.
Legal dimensions
At or under these figures, no oversize permit is required in Illinois.
- Width
- 8′6″
- Height
- 13′6″
- Gross weight
- 80,000 lb
- Overhang
- 3′ front, 4′ rear
- Single axle
- 20,000 lb
- Tandem
- 34,000 lb
- Tridem
- 42,500 lb
Routine permit limits
Above legal dimensions and up to these figures, Illinois issues a permit as routine business. Beyond them the load becomes a superload, reviewed case by case.
- Length
- 145′
- Width
- 14′6″
- Height
- 15′, with 3″ of clearance required
- Single axle
- 24,000 lb
- Tandem
- 48,000 lb
- Tridem
- 60,000 lb, with no single axle above 21,000 lb
- Quad
- 60,000 lb, or up to 100,000 lb on a superload permit
Escort requirements
A load reaching any of these figures needs an escort in Illinois — the figure is the first size that requires one, so a load measuring exactly this much already needs it.
- Width
- 14′7″
- Height
- 14′6″
- Length
- 110′1″
When the load may move
Permit validity. Permits are valid for five days.
Operating time. Within 12′ wide, 13′6″ high and 200′ long: around the clock, with one civilian escort in darkness. Within 14′6″ wide and 15′ high: daylight, seven days a week. Beyond that: daylight Monday to Friday, plus Saturday morning until noon. Overweight-only loads may travel continuously.
Restricted travel. Loads 14′6″ to 16′ wide may move only 9 AM to 3 PM, Monday to Friday, in Cook, DuPage, Lake, Kane, Madison, McHenry, Monroe, St. Clair and Will counties. Cook County expressways cap oversize traffic at 12′ wide, 13′6″ high and 120,000 lb. No travel from noon the day before a major holiday or holiday weekend.
Worth knowing
- Structural loads — beams, poles, pipe and culverts — need no permit up to 80′ in daytime, Monday to Friday.
- Farm implements need no permit when width is the only oversize dimension, in daylight.
- Legal length is 53′ for the semitrailer on designated highways and 65′ overall elsewhere.
- Legal width drops to 8′ on non-designated routes.
- Superload thresholds: 5 axles above 100,000 lb gross or 44,000 lb on a tandem group; 6 or more axles above 120,000 lb gross or 48,000 lb on any group.
Illinois permits, answered
Can an oversize load travel at night in Illinois?
Within 12′ wide, 13′6″ high and 200′ long, yes — around the clock, with one civilian escort during darkness. Larger loads are daylight only.
What are the Chicago-area restrictions for wide loads?
Loads between 14′6″ and 16′ wide may move only between 9 AM and 3 PM on weekdays across nine counties including Cook, DuPage, Lake and Will. Cook County expressways separately cap oversize traffic at 12′ wide and 13′6″ high.
Do steel beams need an Illinois permit?
Not up to 80′. Beams, poles, pipe and culverts travel exempt in daytime, Monday to Friday.
When does the Illinois holiday ban begin?
At noon on the day before the holiday or holiday weekend, so half a working day disappears earlier than a midnight rule would suggest.
Do farm implements need an Illinois oversize permit?
Not if width is the only dimension that is oversize and the move happens in daylight.
Crossing more than Illinois?
A permit is per state. If the route leaves Illinois, these are the states it most likely enters.
Get a permit quote for Illinois
Enter the load once and the estimator prices every state on the route, flags where an escort is required, and turns the quote into an order.
Price a permit for Illinois →Compiled from published state DOT sources. Regulations change — confirm the current rules before dispatch. Last reviewed 2026-07-30.