Accessible signage is not as easy to specify as we might think.  Signage in buildings are used to assist visually impaired and mobility impaired patrons to find their way
around.  Each have their own requirements.  This Blog explains two
types of signage and what specifications are found in the ADAAG and other
accessibility guidelines.

mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:minor-bidi; color:#1F497D;mso-themecolor:dark2"> 

http://abadiaccess.blogspot.com/2010/06/accessible-signage.html