December 22, 1999

TO:                  All Design Section Staff

FROM:            C. C. Ruth

PHONE:          705-7209

SUBJECT:       Bridge Traffic Barrier Policy

Please refer to Section 8.3.2A of the Bridge Design Manual. The guidelines shall be augmented with the following criteria as it relates to the proper use of the bridge traffic barrier standards:

    The standard approach for new bridge rails is to use a 32" safety shape (F Shape) concrete on all interstate and major highway routes. Use a Single Slope concrete bridge rail when there are Single Slope concrete barriers on grade in the median for approaches to bridges or for continuity within a corridor (See Highway Design Manual Section 710 for additional background and criteria). The Standard SIngle Slope bridge rail is 34" high to be consistent with the heights being used on grade applications.

    Use taller 42" safety shape or single slope bridge rails on interstate or freeway routes where accident history suggests a need or where roadway geometrics increase the possibility of larger trucks hitting the barriers at a high angle (such as on ramps for freeway to freeway connections with sharp curvature in the alignment).

This instructional memorandum shall be in place and official until the BDM is amended to include these guidelines.



cc:   J. A. Weigel

       F. Higgins
       Z. Y. Fahoum
       Dick Albin, Design - 47329