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Commercial Vehicle Services
7345 Linderson Way SW
PO Box 47367
Tumwater, WA 98504-7367

Superload Requirements

A superload is a vehicle or combination with a non-divisible load exceeding sixteen feet wide, sixteen feet high, 125 feet of load length, or 200,000 pounds.

Follow these steps to receive a permit for a superload:

  1. Applications for loads over 200,000 pounds must be submitted in writing and received at least 30 days before the proposed date of movement (RCW 46.44.091)(5)).  Applications for loads over sixteen feet wide or sixteen feet high must be submitted in writing at least seven (7) calendar days before the proposed date of movement.  A request for Approval of Oversize/Overweight Movement (Form 560-022) may be requested from Commercial Vehicle Services.

  2. The motor carrier or shipper must provide the following information to Commercial Vehicle Services (WAC 468-38-405 Superload Movement Criteria):

    • Evidence describing the purpose of the movement and whether the move is necessary (and in the public interest).  Written certification by military officials or officials of public or private power facilities that the movement is necessary must also be included when appropriate;

    • The item being transported must be clearly shown to be non divisible.  A sketch or photograph of the item with an explanation of why it cannot be shipped in parts must be provided;

    •  A sketch of the transporting laden vehicle showing axle loadings, axle spacings, tire sizes, tires per axle, width, and height;

    • If the load can be barged or shipped by rail for all or part of the route, the shipper must review those alternatives.  If he wants to show that "it is not reasonable for economic or operational considerations" to ship it by water or rail, he must present whatever data is needed to support that judgment;

    • The applicant must propose a route that he knows is adequate to accommodate the width and height of the laden vehicle, and appears adequate to support the weight of the vehicle and load.  This information is usually requested from pilot car operators who specialize in over dimensional movements.  If the route includes the use of county roads or city streets, the applicant must show that permits from each of those jurisdictions will be issued.  The written request will describe at what point county roads or city streets will be utilized, the name or number of the road or street, and the county or city official who has approved the proposed move using its roads or streets; and

    • A traffic control plan depicting the route and specific procedures that will be followed to control traffic flow along the route, including estimated traffic delays, lane restriction, use of escort vehicles and flag persons, movement of overhead obstacles, railroad schedules* for crossings, and provisions for emergency vehicles to navigate around the load.


      *Note:  Physical examination of all railroad crossings by the carrier of his designee is critical.  A lack of sufficient ground clearance can be fatal. 

  3. If the department determines the movement is necessary, an analysis of bridges and pavements will be initiated.  If the analysis requires significant expenditure of time by the DOT staff, the applicant may be asked to share in those costs. 

  4. If the structures, clearances, and pavements are judged adequate, the permit will be issued or will be further negotiated to define its terms (escort requirements, hours of movement, etc.)