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Bridge Load Ratings

Load rating policies and procedures are administered by the Bureau of Bridges & Structures to ensure public safety and to comply with federal regulations and state statutes.  The Bureau determines the safe load capacity of various types and sizes of structures from complex bridges such as trusses, cable-stayed and tied arches to simple culverts and single span bridges.

Questions?  Please review the Q&A pdf in the Resources tab.  You may also email DOT.Bridge.Ratings@illinois.gov.  Your question will be responded to as quickly as possible and may be included in the Q&A pdf if necessary (names withheld).


AASHTOWare™ Bridge Rating (BrR) software is available to consultants and local agencies for use on Illinois structures, at no charge.  AASHTOWare™ Bridge Design (BrD) software is available at a discounted rate to consultant and local agencies for use on Illinois structures.  All AASHTOWare licenses are valid July 1st through June 30th of the following year.  You will be required to renew your license each year prior to July 1st.  AASHTOWare Bridge Rating is the preferred software to perform load ratings.

Please do not contact AASHTO and ProMiles for technical support.  IDOT provides technical support to all licensees under this reduced fee program.  Technical support questions should only be sent to DOT.Bridge.Ratings@illinois.gov

For structure types that cannot be analyzed using AASHTOWare Bridge Ratings, please contact the Bureau for further guidance.

BrR License Request 

The following libraries have been prepared by the Bureau of Bridges & Structures for IDOT specific elements.  Their use is not mandatory but are being shared here in an effort to reduce error and cost; see disclaimer below.  To ensure greater accuracy for all, please notify technical support of any discrepancies found.  Revisions to these files will be made as AASHTOWare and load rating policies change.  Notification of revisions will be made through IDOT’s Bureau of Bridges & Structures subscription service.

BrR Libraries (Agency Specific)
(Save file to your computer)

Illinois Rating Vehicles (revised November 2021)
Prestressed Shapes (revised November 2021)
Materials (revised November 2021)
Appurtenances (revised November 2021)


Q&A (Revised: November 2021)

Structure Load Rating Summary (form BBS 2795)

Load Rating Inspection Report (form BBS 2710)

Structural Services Manual (Revised: June 2017)

Gusset Plate Evaluation Guide (June 18, 2014)

Notice of Disclaimer: IDOT offers the files, documents, and applications from this web page on an “as is” basis. All warranties and representations of any kind with regard to any downloaded file are disclaimed, including the implied warranties of merchantability and fitness for a particular use. Under no circumstance will IDOT or any of its employees be liable for any consequential, incidental, special or exemplary damages even if apprised of the likelihood of such damages occurring. IDOT does not warrant the files, applications or documents against deficiencies of any kind. The use of any of the documents, files or applications for work which is under contract, does not relieve the consultant from any obligations assumed by the contract, or from complete and proper fulfillment of the terms of the contract, nor does it entitle the consultant to compensation for damages or loss which could be attributed to such use.