The methodology is presented in a general format utilizing load and resistance factors. This procedure allows for combining probability theory@ statistical data and engineering judgment into a rational decision making tool. In particular@ the procedure allows the engineer to use site specific information in a consistent manner to improve@ if necessary@ his judgment on the safe rating level for a particular bridge. In addition@ the format incorporates existing methodology for considering local laws and regulations and methods of calculation. Purpose These proposed guidelines establish a methodology for rating existing bridges.