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Iowa Oversize Permits Information


Iowa Oversize Permits are valid for 5 days. Driver must have the Iowa DOT permit before entering the state.

Operating Time

Permitted vehicles up to 100′ in length, 11′ width, 14’4 height may have continuous travel seven days a week (24/7), provided travel is on the roadway with a minimum width of 22 feet and minimum lane width of 11 feet, and with safety lighting as specified on Iowa provisions sheet. Larger loads may travel one-half hour before sunrise to one-half hour after sunset, including Saturdays and Sundays.


No travel allowed starting 12 noon the day prior to major holidays and holiday weekends. Des Moines I-235 travel prohibited from 7:00 – 9:00 A.M. and from 4:00 – 6:00 P.M. Monday through Friday. Other highways in Des Moines can be included under the curfew at officer’s discretion if traffic is heavy.

Speed Limit

Maximum posted limits unless otherwise specified on permit.

Legal Dimensions

The vehicle must have the following characteristics:

  • Width: 8’6″
  • Height: 13’6″
  • Length: 53′ semi-trailer and load. (Overhang which results in over 53′ semi-trailer and load length is not legal without Iowa Oversize Permit. Steel pipe, beams and constructions materials are NOT exempt.)
  • Weight: 80,000 Gross; Single – 20,000; Tandem – 34,000; Tridem – 42,000 (w/ minimum 8’1″ axle spacing)

Routine Iowa Oversize Permit Limits

  • Width: 18′
  • Height: 18′
  • Length: 120′
  • Weight: Single – 20,000; Tandem – 40,000; Tridem – 60,000; Steer Tire – Permit does not break out the steer axle weight but enforcement goes by the single (steer) tire weight rating (on the side of the tire) times two.

*Note: You must be licensed for as much as you wish to permit in Iowa. Loads exceeding these dimensions or weight are considered as super loads.


  • On 4-lane roadways: Width: 14’6” to 16’6″ – 1 rear escort pilot car or 2 amber revolving or strobe lights (one on the power unit, one on rear extremity of vehicle or load). Over 16’6″ – 1 escort pilot car.
  • On 2-lane highways: Width: When width exceeds one-half of roadway width up to and including 14’6″ – 1 front escort pilot car. Width over 14’6″ – 1 escort pilot car. An amber or strobe light on the power unit and on the rear extremity of the vehicle or load may be used instead of an escort if the width is up to and including 14’6 and exceeds one-half of the roadway and lane width is 12 feet or more with sufficient shoulders.
  • On all highways:
    • Height: Over 14’6″ – 1 escort pilot car with a height pole.
    • Length: Over 85′ – 1 escort pilot car or amber revolving light. Over 120′ – 1 escort pilot car
    • Overhang: Front projection over 25′ or rear over 10′ – 1 escort pilot car or amber revolving light or strobe light on the rear of the load for rear overhang over 10′).

Security Measures

“Oversize Load” signs and flags are required when a vehicle and load exceeds 75′ in length, 8’6 width, and/or 14’4 in height. Flags are required for rear overhang exceeding 4 feet on all permitted vehicles/ loads. Flags should be mounted at each front corner of the towing unit, at each rear corner of the load, and at any wide points/protrusions of the load. An amber revolving light at least 7″ high and 7″ in diameter is required on the towing unit whenever length exceeds 85′, front overhang exceeds 25′ or rear overhang exceeds 10′ (light should be on the load in the rear) or weight exceeds 80,000 lbs. An escort can be used in lieu of amber light.

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