Evaluation of Alternative Procedures for Setting Curve Advisory Speed

Abstract

This paper examines procedures for setting curve advisory speeds, identifies issues associated with these procedures, and describes a proposed procedure that overcomes many of these issues. The proposed procedure consists of three elements: a criterion for setting the curve advisory speed, a method for determining this speed, and an engineering study method that confirms the need for an advisory speed plaque. One conclusion is that challenges associated with the use of the ball-bank indicator hinder achieving curve advisory speeds that are uniform in curves and consistent with driver expectation. The proposed procedure is shown to overcome these challenges.