Frequently Asked Questions

Oversize Overweight Permits



What is kingpin and how is it measured?

Tennessee over-length law uses kingpin to determine if the vehicle is over length.  Some carriers get kingpin and bridge law mixed up. Where bridge law is the distance from the kingpin to center of single axle or center of tandem, the over-length kingpin is measured from the kingpin to the rear of the trailer or overhang. If the kingpin is over 50 feet, the vehicle or load is over length and needs a permit.

How do I know if my vehicle needs a permit?

According to Tennessee Law, a vehicle or combination of vehicle and load requires a permit if any of the following dimensions are exceeded:

  • Width:  8 feet and 6 inches
  • Height: 13 feet and 6 inches
  • Length:
    • 50 feet for truck tractor + semi-trailer combination
    • 28 feet and 6 inches for semi-trailers and trailers used in truck tractor-semi-trailer-trailer combination
  • Overhang: 60 inches or 5 feet (total for both front and rear)
  • Weight:
    • 20,000 lbs for single axle
    • 34,000 lbs for tandem group

A permit is required if the vehicle or combination of vehicles and loads is overweight, over-width, over-length, or over-height. Commodity being hauled must be loaded so that the vehicle or vehicle and load combination presents the least dimension and exposure to the motoring public.

What types of  Annual Permits are available at the TDOT Permit Office?
  • Pick which weight class would best fit your needs:
    • 100K : $750.00
    • 120K : $1,500.00
    • 140K : $2,250.00
    • 155K : $3,000.00
    • 165K : $3,500.00
  • If you need only dimensions or dimensions as well as weight, select which dimensions best fit your needs:
    • Height 13’10” : $100.00
    • Width 13’6” : $100.00
    • Length 90’ : $100.00
Type Total Length Width Height Gross Weight Price
14ft Mobile Home 120' 14' 14'2" n/a $1,000.00
16ft Mobile Home 120' 16' 14'2" n/a $2,000.00
Roof Trusses 85' 14' 13'10" n/a $500.00
Ocean Going Container n/a n/a n/a 90,000 lbs $750.00
Commercial Boat 85' 14' 13'10" n/a $500.00
What is the cost of a Tennessee OS/OW Permit?

There are a variety of factors that make up the cost of a TDOT OS/OW permit.  Below are the general parameters for pricing; however, this is not a comprehensive list.

  • Excessive length or height: $20.00
  • Excessive weight:
    • $20.00 plus six cents ($.06) per ton-mile.
  • Excessive Width
    • greater than eight feet six inches (8'6"), but not more than fourteen feet (14') - $20.00
    • greater than fourteen feet one inch (14'1"), but not more than sixteen feet (16') - $30.00
    • greater than sixteen feet one inch (16'1) & up: $30.00 plus $5.00 for each added foot or fraction
What forms of payment are accepted?

Many forms of payment are accepted including:

  1. Company Check
  2. Cashier’s Check
  3. Money Order
  4. Credit Card (Visa, Master Card, AMEX, Discover)
  5. Escrow Accounts may be used for Single Trip Permits   
What are some important escort and safety requirements I need to know?

Schedule and Route Information

  • Movement is not allowed from sunset to sunrise, anytime on Sunday, or anytime on New Year’s Day, Memorial Day, Independence Day, Labor Day, Thanksgiving Day, and Christmas Day.
  • When routing is applicable, the permitted vehicle will not travel any route other than the one permitted. If the permitted route becomes impassable, the permitted party is to halt travel and call the permit office for alternate routing.      

Safety Requirements

  1. The escort vehicle must be a properly-licensed, single-unit vehicle (passenger automobile, pickup truck, or SUV) that allows an unobstructed 360˚ view for safety. No flatbed trucks, service vehicles, and no vehicle towing a trailer can be used as an escort vehicle.
  2. An escort vehicle should allow for an unobstructed 360° view for safety. It should be equipped with two 18-inch square red flags mounted on the roof and two rotating or strobe amber lights that are visible 360˚.
  3. The escort’s headlights are to be on low beam.
  4. A yellow sign shall be mounted on the front and rear of any overwidth or overlength vehicle or load. When escorts are required, a yellow sign should be placed on the front of the escort vehicle (for front escorts) or the rear of the escort vehicle (for rear escorts). The sign shall read “OVERSIZE LOAD” and be five-feet wide by 12 inches high with ten-inch black letters with 1.5-inch brush stroke. The rear sign must not obscure the rear signals or lighting system. The wording “WIDE LOAD” is not an acceptable alternative.
  5. 18-inch square red flags are to be placed on all corners of an oversized vehicle or combination of vehicles and loads.
  6. For mobile homes, the approved lighting system includes two rotating or strobe amber lights that are visible 360˚ placed at the rear corners of the mobile home. The lighting system should be controlled from inside the tractor cab with a warning device to alert the driver in the event of the malfunction. Two-way communication is required at all times with all units of the convoy.
I have a commercial vehicle question. Who do I call?

For all questions pertaining to commercial vehicles, please call (615)743-4990.

My TN Single Trip Permit has been issued, but (another state) won’t let me enter their state on that route. What can I do?

If it has been less than 8 hours since the permit was issued, then you can amend the route on the permit. This will send the permit back through the TOOPS system and will require staff review. If it has been more than 8 hours since the permit was issued, then you will have to reapply for a new single trip permit and submit a void request form. The void request form can be found under OS/OW Permit Resources.

When can I amend my permit?

Single Trip Permits can be amended up to eight (8) hours once issued. Please see OS/OW Permit Amendments section or OS/OW Permit Resources > Processes, Policies, & Memos > Permit Amendment Information (PDF) for more information.

When can I void my permit?

Single Trip Permits can only be voided up to four (4) days after the start date/effective date. If a Single Trip Permit is able to be amended, opposed to voided, it must be amended. If unable to amend, then a void request will be considered. A complete void request, including reorder number, must be submitted no later than four (4) days from the start date/effective date.

What can I do when my truck breaks down while in route?

This is handled on a case by case situation. Generally, a new Single Trip Permit will need to be ordered with the new truck’s information. Typically speaking, the permit fees will be waived for the new application. However, as mentioned, this is handled on a case by case situation.

I’m having issues with TOOPS. Who do I call?

For all TOOPS issues such as a password issue or a system error message please contact the TDOT IT Service Desk at: (615)770-1700 or Toll Free at 844-593-5300; Monday through Friday (except holidays) 8:00am to 4:30pm CST. For all other Overweight & Oversized Permit related support issues please continue to contact us at or at (615)741-3821; Monday through Friday (except holidays) 8:00am to 4:30pm CST.

How much money do I need to set up an account to order Single Trip Permits directly with the state?

In an effort to make TOOPS more accessible, we have lowered the escrow deposit to $1,000. All the necessary documentation required to set up an account with the state is located under OS/OW Permit Resources>State Contract. If you have any questions regarding setting up an account with the state, please contact us at or (615)741-3821.

How much money do I need to keep in my escrow account?

The amount required varies per company. Whatever amount your company would need to process thirty (30) days worth of permits is what must remain in your account at all times.

What is the criteria for an auto-issue Single Trip Permit?

Overdimensional: up to 16' in width and up to 14'6" in height Mobile Homes: up to 16' in width and up to 14'6" in height Roof Trusses: up to 16' in width and up to 14'6" in height Ocean Going Container: up to 90,000 lbs overall gross, maximum of 20,000 lbs on an axle, passes load screening Other: up to 16' in width and up to 14'6" in height, up to 150,000 lbs overall gross, maximum of 20,000 lbs on an axle, passes load screening

When can I get my single trip permit approved and released back to me?

Single Trip Permits will only be approved up to three (3) days prior to the permit’s start date. For example, if a permit has a start date of December 4th, it may be approved on December 1st. (Holiday exceptions may occur.) This policy helps reduce voids and amendment issues. Please remember that Single Trip Permits can only be voided up to four (4) days after the start/effective date; and that Single Trip Permits can only be amended within the first 8 hours after approval.

My load is over sixteen feet (16’) wide, therefore I must submit a Shipper’s Letter with my Single Trip Permit request. What information needs to be included in a Shipper’s Letter?

The following information must be included in a proper shipper’s letter:

  • Company/Carrier Header 
  • Load Description
  • Load Dimensions
  • Can it be transported by barge, rail, or other means?
  • Is this in the interest of public welfare, safety, health, or defense?
  • What is the loads proposed route?
  • Proposed traffic control

Authority: Rules and Regulations for Overweight & Overdimensional movements on Tennessee Highways 1680-7-1.08 : Generally, movements in excess of sixteen feet (16’) will not be permitted. A movement needed in the interest of the public welfare, safety, health, or defense may be permitted as provided in Rule 1680-7-1-.04 upon submission of proof of necessity, provided the movement is not considered to be detrimental or unsafe to the traveling public and the highway can accommodate the movement.

My load has multiple pieces and is loaded end to end or side by side. How should I list it in the load description on my single trip application?

Whenever hauling multiple pieces, you are only allowed to create one dimension. When completing the load description portion, it should list the number of pieces loaded, for example: “4 A/C Units End to End”. This way THP can verify the load at the scale house, and ensure that additional dimensions are not being created.