Abstract
A brief historical perspective on the development of the rate-quality control method and its use in the identification of hazardous roadway locations is presented. The evolution of the formulas used in the rate-quality control method from their origin in the late 1950s to their present form is traced. The derivation of the basic formulas used in the method is also presented and discussed. It is suggested that, contrary to assertions in the literature, the accuracy of the equations used in the rate-quality method is not improved by eliminating the normal approximation correction factor from the original equations. The need for the correction factor is particularly apparent at higher probability levels. Charts are provided for determining an appropriate correction factor for those who may wish to incorporate these factors into the equations.
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