Mick, as you design roads for a living I am interested in what formula is used to determine advisory limits. Many times whilst driving on the open road (i.e. 100K limited) I have seen Attachment 127501 only to find that the bend can be safely negotiated at 100K. These advisory signs signs are just that "advice on a recommended speed/warning to negotiate a particular hazard" the trouble is you never know when the 80K bend sign means just that 80K no more.