Legal size limits without a permit
| Measurement | Illinois legal limit |
|---|---|
| Height | 13'6" |
| Width | 8'6" |
| Front Overhang | Confirmed at filing |
| Rear Overhang | Confirmed at filing |
Axle and gross weights
How much each axle group and the whole vehicle can carry in Illinois, without a permit and with an overweight permit.
| Axle group | Legal limit | With a permit |
|---|---|---|
| Steer axle | Confirmed at filing | Confirmed at filing |
| Single axle | 20,000 lbs | No single fixed ceiling published; evaluated per Federal Bridge Formula/route |
| Tandem axle | 34,000 lbs | No single fixed ceiling published; evaluated per Federal Bridge Formula/route |
| Tridem axle | Confirmed at filing | Confirmed at filing |
| Quad axle | Confirmed at filing | Confirmed at filing |
| Gross weight | 80,000 lbs | No fixed statewide cap published; overweight permits evaluated case-by-case via bridge analysis |
Superload: Loads exceeding 15' high / 145' long / 14'6" wide move into IDOT's 'Superload' fee category, requiring individual route/bridge review
Permit types we file in Illinois
Single-Trip PermitOne-way movement, valid 5 working days.
Round-Trip PermitSame route in reverse, valid 10 working days.
Limited Continuous Operation Permit3-month or 1-year authorization for a specific vehicle/load type.
Maximum dimensions with a permit
| Dimension | Maximum with a permit |
|---|---|
| Length | 145 ft (practical maximum before Superload fee category) |
| Width | 14'6" (practical maximum); up to 16' possible with 3 escorts |
| Height | 15' (practical maximum); up to 18' possible with escort/State Police |
| Rear Overhang | Confirmed at filing |
IDOT's Table 2 fee schedule treats any dimension over 15' high, 145' long, or 14'6" wide as triggering the Superload fee category and individual route review.
Escorts and travel restrictions
Escort & pilot car rules
- One civilian escort required for loads exceeding 14'6" wide, 14'6" high, or 110' long.
- Two civilian escorts required when a load exceeds a combination of the above thresholds.
- Three civilian escorts required for loads exceeding 16' wide, 18' high, or 145' long.
- Illinois State Police escort required for loads exceeding 18' wide, 18' high, or 200' long.
When you can travel
- Loads ≤12' wide / ≤13'6" high / ≤115' long may travel 7 days a week, sunrise to sunset.
- Larger oversize loads: Monday-Friday sunrise to sunset; Saturday sunrise to noon; no Sunday travel.
- Overweight-only (legal-dimension) loads may move 24/7.
- Travel restricted around 6 major holidays and holiday weekends.
Signs, flags and lights
Most states require
- An “OVERSIZE LOAD” banner on the front of the truck and the rear of the load.
- Red or fluorescent orange warning flags at each corner and at the widest points of the load.
- Amber warning lights or clearance lights when moving at night, where night travel is allowed.
Illinois specifics
- Banner size, flag size and light rules for Illinois are listed on your permit.
- We include them in your permit notes so your driver has them before the trip.
Rules change. Limits and requirements are set by IDOT and can change. We confirm the current rules for your exact load before filing.