Permits
Illinois Oversize Permits are valid for 5 days.

Operating Time
Overweight permit loads with legal dimensions are authorized to move 24 hours a day, 7 days a week.
Overweight and/or Over-dimension permit loads with dimensions equal to or less than 10’0” wide, 13’6”’ high, 200’ long are authorized to move 24hours a day, 7 days a week with one additional civilian escort when traveling during the hours of darkness.
Overweight and/or Over-dimension permit loads with dimensions equal to or less than 14’ 6” wide, 15’ high, 200’ long are authorized to move from½ hour before sunrise until ½ hour after sunset, 7 days a week.
Overweight and/or Over-dimension permit loads with dimensions equal to or less 16’0” wide, 17’ high are authorized to move from ½ hour before sunrise to ½ hour after sunset Monday through Friday, and from ½ hour before sunrise until noon, Saturday (unless specified otherwise on the provision sheet or permit).
Overweight and/or Over-dimension permit loads with dimensions greater than 200’ long are authorized to move from ½ hour before sunrise to ½hour after sunset Monday through Friday. No Saturday or Sunday movement is allowed (unless specified otherwise on the provision sheet or permit).
Overweight and/or Over-dimension permit loads with dimensions greater than 16’0” wide, 17’0” high, are authorized to move from 9:00am CST to3:00pm Monday through Friday. No Saturday or Sunday movement is allowed (unless specified otherwise on the provision sheet or permit).

Restrictions
Permit loads on Expressways in Cook County are restricted to a maximum of 120,000 pounds, 12′ wide and/or 13’6″. Several special restrictions apply in Cook County, as listed on provision sheets (General Provisions B). Loads over 14’6″ wide up to and including 16′ wide are limited to the hours of 9:00 a.m. – 3:00 p.m. Monday through Friday in Cook, DuPage, Lake, Kane, Madison, McHenry, Monroe, St. Clair and Will counties. Over 16′ wide may have additional restrictions. No travel from noon the day prior to major holidays or holiday weekends. Maximum width is 12′ and maximum height is 14’6″.

Maximum gross weight allowed is 120,000. Length exceeding 100′ needs prior approval and special permit. Separate permits must be obtained from the Illinois State Toll Highway Authority.

Length limitations do not apply (over dimensional permit not needed) for vehicles operated in the daytime, Monday through Friday, when transporting beams, poles, pipe, culvert or other objects of a structural nature 80′ or less in length (overall length 100′ or less). Farm tractors and other implements of husbandry may be hauled without a permit during daylight hours (including weekends) when over width only. Illinois Oversize Permits is still needed if over 13’6 high, or overweight.

Speed Limit

Maximum speed shall be 5 m.p.h. below the posted speed limit, EXCEPT when otherwise specified in the permit. Legal weight, legal height movements up to and including 10 feet wide are allowed to travel at the legal maximum speed limit.

Legal Dimensions
The vehicle must have the following characteristics:

Width: 8’6″ on designated highways, 8′ on non-designated
Height: 13’6″
Length: 53′ semi-trailer* on designated highways, 65′ overall on non-designated.
Overhang: 3′ front, 4′ rear. More rear overhang is allowed if within legal length limits.
Weight: 80,000 Gross Single – 20,000; Tandem – 34,000; Tridem – 42,500
*Note: Kingpin to the center of rear axle not over 45’6″, or needs to be permitted.

Routine Illinois Oversize Permit Limits
Width: 14’6
Height: 15′ (depending on overhead clearances, 3″ clearance required)
Length: 145′
Weight: Single – 24,000; Tandem – 48,000; Tridem;–;60,000 (no single axle to exceed 21,000); Quad – 60,000 on standard permit, up to 100,000 with a super load permit.
*Note: Overweight applications get treated as superloads when: On 5 axles, grossing over 100,000 pounds and/or over 48,000 pounds on a tandem group. On 6 or more axles, grossing over 120,000 pounds and/or over 48,000 pounds on any axle group.

**Note on Lift or Pusher axles: Maximum weight variance between axles in a group is 2,000 pounds. Over 16′ wide or 17′ high will require a field or district engineering investigation. Over 17′ high, all overhead utility companies must be contacted and documentation must be provided

***Note: Maximum height on Chicago highways is 13’6″. No interstate routing is allowed for over 15’9” height. Height of 16′ or more requires detailed route survey.

Escorts
Width: Over 14’6 – 1 escort pilot car; over 16′ – 3 escort pilot cars; over 18′ – State Police escort.
Height: Over 14’6 – 1 escort pilot car with high pole; over 18′ – 2 escort pilot cars and State Police.
Length: Over 110′ – 1 escort pilot car; over 145′ – 3 escort pilot cars; over 200′ – State Police.
*Note: Loads exceeding any two of the above dimensions – 2 escort pilot cars.

Security Measures
Flags are required on the extremities of all oversize vehicles or loads and all protruding objects. “Oversize Load” signs are required on loads over 10′ wide, 14’6 high and/or 75′ long. All oversize/overweight permit loads must display an operable oscillating, rotating or flashing amber light or lights on the tractor. Light(s) must be visible from both sides and the front, and must be strong enough to be seen for at least 500 feet in the daytime. When visibility of the light is blocked from the rear, and for loads over 80′ long or combinations over 100′ long require a second light mounted 10′ of rear of the object, as high as practical over it.