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  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 Michael Baker International for technical support.  IDOT provides technical support to all licensees under this reduced fee program.  Technical support questions should only be sent to

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

BrR License Request (Coming Soon)

BrR Libraries (Agency Specific)

Illinois Posting Vehicles (Save file to your computer)


Q&A (Revised: July 1, 2017) (Coming Soon)

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)


IDOT Preferences when using BrR (Coming Soon)

Guidelines for Estimating Strand Loss in PPC Deck Beam Bridges