Illinois Truck Weight and Size Limits
Legal limits for a truck in Illinois without a permit: Interstate axle and gross weights, height, width, and semitrailer length, each with its official source.
Data pending verification
Some official figures this page relies on haven't been confirmed against the source yet. Don't rely on results here until this notice is gone.
What's pending
- weight-limits/states/illinois
Illinois limits at a glance
| Limit | Illinois | Source |
|---|---|---|
| Interstate gross weight | 80,000 lb | 23 CFR 658.17, Weight (eCFR) |
| Interstate single axle | 20,000 lb | 23 CFR 658.17, Weight (eCFR) |
| Interstate tandem axle | 34,000 lb | 23 CFR 658.17, Weight (eCFR) |
| Width (National Network) | 102 in | 23 CFR 658.15, Width (eCFR) |
| Height | Pending verification | FHWA, Compilation of Existing State Truck Size and Weight Limit Laws (Report to Congress, May 2015), Appendix A: Illinois |
| Semitrailer length | Pending verification | FHWA, Compilation of Existing State Truck Size and Weight Limit Laws (Report to Congress, May 2015), Appendix A: Illinois |
| Grandfathered semitrailer length | 53 ft | 23 CFR part 658, Appendix B, Grandfathered Semitrailer Lengths (eCFR) |
Interstate weight limits
Federal law sets the Interstate limits at 20,000 lb on a single axle, 34,000 lb on a tandem, and 80,000 lb gross, with the bridge formula on every axle group (23 CFR 658.17). States may keep higher limits they had before the federal limits took effect ("grandfather rights").
Bridge formula check with Illinois limits
A 5-axle tractor-trailer is filled in. Change the spacings and weights to match your rig; the limits for single axles, tandems, and gross are Illinois's Interstate limits.
Your result
Illinois limits off the Interstate
FHWA's summary of Illinois law for trucks in regular operation (no permit), including non-Interstate highways. It reflects state law as of October 1, 2012; check the state for later changes.
- Single axle
- 20,000 lbs.
- Tandem axle
- 34,000 lbs.*
- Tridem axle
- 42,500**
- Gross weight
- 80,000 lbs.
- Other
- 800 lbs. per inch width of non-pneumatic tire when any axle exceeds 16,000 lbs.
Where Illinois allows more than federal limits
- Illinois State statute allows for several axle and GVW exemptions for various types of vehicles.
- Vehicles registered as Special Haul Vehicles (SHV) have various axle and bridge formula exemptions except when using the National System of Interstate and Defense Highways.
Height, width, and length
- Width: 102 inches. States may not set a width limit of more or less than 102 inches on the National Network (23 CFR 658.15(a)). Permits can allow wider loads.
- Height: pending verification. There is no federal height limit; each state sets its own.
- Semitrailer length: pending verification.
- Grandfathered semitrailer length: 53 ft. The minimum semitrailer length the state must allow in a tractor-semitrailer combination on the National Network, based on lengths legal in the state on December 1, 1982. Federal law also requires at least 48 ft (23 CFR 658.13(b)(1)).
Over these limits you need a permit. Illinois oversize/overweight permits (217-785-1477).
Illinois compared with neighboring states
| State | Gross | Single | Tandem | Height | Semitrailer |
|---|---|---|---|---|---|
| Illinois | 80,000 lb | 20,000 lb | 34,000 lb | Pending | Pending |
| Indiana | 80,000 lb | 20,000 lb | 34,000 lb | Pending | Pending |
| Iowa | 80,000 lb | 20,000 lb | 34,000 lb | 13 ft 6 in | 53 ft in a truck tractor-semitrailer c… |
| Kentucky | 80,000 lb | 20,000 lb | 34,000 lb | 13 ft 6 in on highways the Transportat… | 53 ft on designated highways |
| Missouri | 80,000 lb | 20,000 lb | 34,000 lb | 14 ft on the Interstate and designated… | 53 ft |
| Wisconsin | 80,000 lb | 20,000 lb | 34,000 lb | 13 ft 6 in | 53 ft if the kingpin to axle distance … |
Sources
Source: 23 CFR 658.17, Weight (eCFR) · Last verified Sep 28, 2026
Source: FHWA, Compilation of Existing State Truck Size and Weight Limit Laws (Report to Congress, May 2015), Appendix A: Illinois · Effective Oct 1, 2012 · Last verified Sep 28, 2026
Source: 23 CFR 658.15, Width (eCFR) · Last verified Sep 28, 2026
Source: 23 CFR part 658, Appendix B, Grandfathered Semitrailer Lengths (eCFR) · Last verified Sep 28, 2026
Source: FHWA, Oversize/Overweight Load Permits: State permit contacts · Last verified Sep 28, 2026
Limits change, and cities, counties, and posted bridges can set lower ones. Check with Illinois before you run a load near the limits. Page data last verified Sep 28, 2026.