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Do you have any recommendations for the design of curb under barrier transitions.  I know 4” sloped curb, but what is the transition form sloped too vertical?  Below is the detail we have used for years.  I am having issues with this detail and the new bridge endpost.  Just curious how much flexibility I have redesigning this detail.

A few comments:

• In years past, AGTs may have only been tested and/or approved for use with a 4” tall wedge shaped curb.  However, we have learned much in recent years. Multiple AGTs have been successfully tested with vertical shaped curbs instead of wedge-shaped curbs.  Also, a recent NCHRP project (report 1018) showed that the shape of the curb is less important than height of the curb in terms of vehicle traversals and trajectories.  Thus, a vertical curb (type A) would be a an option to the wedge shaped curb.
• Many DOTs are aligning the toe of the curb with the face of the buttress/bridge railing and extending the curb profile into the lower taper of the buttress.  Examples of this are shown below (from report no. TRP-03-369-20).  The same could be done for a vertical curb if desired.

A few comments:

• In years past, AGTs may have only been tested and/or approved for use with a 4” tall wedge shaped curb.  However, we have learned much in recent years. Multiple AGTs have been successfully tested with vertical shaped curbs instead of wedge-shaped curbs.  Also, a recent NCHRP project (report 1018) showed that the shape of the curb is less important than height of the curb in terms of vehicle traversals and trajectories.  Thus, a vertical curb (type A) would be a an option to the wedge shaped curb.
• Many DOTs are aligning the toe of the curb with the face of the buttress/bridge railing and extending the curb profile into the lower taper of the buttress.  Examples of this are shown below (from report no. TRP-03-369-20).  The same could be done for a vertical curb if desired.