Department of Transportation
IDOT
Illinois • United States of America
The Illinois Department of Transportation (IDOT) oversees over 16,000 centerline miles of state highways forming the backbone of one of the nation's most important freight networks. Chicago is the nation's top freight hub, with IDOT managing corridors including I-80, I-88, I-90, I-94, and I-55 serving the metropolitan area. Illinois is also a critical hub for rail freight, and IDOT coordinates intermodal connections between truck and rail. The department administers oversize/overweight vehicle permits, the GettingAroundIllinois.com travel information system, and weight limit enforcement critical for protecting aging infrastructure.
| Official Website | https://idot.illinois.gov/ |
|---|---|
| Data API | https://www.gettingaroundillinois.com/default.htm |
| Founded | 1917 |
| Headquarters | Chicago |
Available Data
Social Media
- @IDOTDistrict1 — IDOT District 1
Illinois Trucking Regulations
Size & weight limits, OS/OW permits, and seasonal restrictions for commercial vehicles
Weight Limits
| Category | Limit |
|---|---|
| Max Gross Vehicle Weight | 80000 lbs |
| Single Axle | 20000 lbs |
| Tandem Axle | 34000 lbs |
Dimensional Limits
| Category | Limit |
|---|---|
| Max Height | 13.6 ft |
| Max Width | 8.5 ft |
| Max Length (Single Unit) | 42 ft |
| Max Length (Combination) | 65 ft |
OS/OW Permits
Seasonal Restrictions Mar, Apr
Spring weight restrictions are applied on a county-by-county and township basis, typically March through April. Posted roads carry reduced weight limits during the spring thaw period. Contact IDOT or the relevant county highway department for current road postings before operating on local routes.
Weigh Station Bypass
47¢/gal
Member
Special Exemptions
Notable Rules
Illinois has one of the highest diesel fuel tax rates in the Midwest. The Chicago metro area imposes additional municipal weight restrictions on non-state roads; carriers must verify local ordinances when routing through Cook County and surrounding municipalities. I-80, I-88, I-290, and I-294 are primary freight corridors.