Illinois Oversize/Overweight Permits: ITAP Guide & Requirements

ITAP Online Permit System

Illinois processes oversize/overweight (OSOW) permits through the ITAP (Illinois Transportation Automated Permits) online portal. Permits are vehicle-specific and valid for 72 hours from the issue time.

Permit Types

Scale Tolerances

Illinois applies the following scale tolerances before a violation is issued:

These tolerances mean that a truck at 82,000 lbs on the scale (with an 80,000 lb GVW limit) would not trigger a violation. However, do not plan loads around tolerances — they exist to account for scale calibration, not to extend your legal limits.

Dual Permit System: IDOT + Tollway

This is the critical detail that catches haulers off guard: the Illinois Tollway requires a SEPARATE overweight/overdimension permit from the IDOT/ITAP permit. An IDOT permit does not authorize travel on Tollway roads, and a Tollway permit does not cover IDOT routes. If your route crosses both systems, you need both permits.

Tollway Permit Process

• Contact the Illinois Tollway directly for overweight/overdimension permits
• Separate application, separate fees, separate routing review
• Tollway may have different routing restrictions than IDOT
• Bridge clearance and weight reviews are Tollway-specific

Movement Restrictions

Oversize Loads

• No Sunday movement (all day)
• No movement on 6 holidays: New Year’s Day, Memorial Day, Independence Day, Labor Day, Thanksgiving, Christmas
• Night movement may require additional lighting and escort vehicles

Overweight Loads (Legal Dimensions)

• 24/7 movement is permitted — no day-of-week or holiday restrictions
• This only applies if your load is overweight but does not exceed legal dimensions

Spring Thaw (Seasonal Posting)

From approximately January 15 through April 15, county authorities can restrict local and county roads to 5 tons per axle for up to 90 days. These postings:

• Apply primarily to local/county roads, not interstates
• Update on Monday and Thursday mornings
• Can change with little notice as weather conditions shift
• Affect the last-mile routing for many oversize/overweight deliveries

Check with the relevant county highway department before routing OSOW loads on non-interstate roads during this period.

What You Need for Your Application

• Vehicle identification and registration
• Load dimensions (length, width, height, overhang)
• Weight per axle and gross weight
• Axle configuration and spacing
• Origin and destination addresses
• Proposed route
• Proof of insurance ($1M minimum recommended)
• Any special requirements (pilot cars, escorts, law enforcement)