RURAL ROADS SPEED INCONSISTENCIES DESIGN METHODS. PART 2. A DESIGN METHOD TO DETERMINE CRITICAL OPERATING SPEED INCONSISTENCIES ON TWO-LANE RURAL ROADS IN THE STATE OF NEW YORK

The second half of the research project was mainly concerned with the practical application of a proposed design procedure to promote design consistency, harmonize operating speed and design speed, and evaluate the effect of lane widening projects on two-lane rural highways. The effect of tangent length on operating speeds between successive curves is addresses for the first time in the present design procedure. A methodology is presented for measuring the consistency of horizontal design as defined by operating speed and accident expectations. Operating speeds and accident rates can be predicted for various lane widths based upon degree of curve and posted recommended speeds. Guidelines for changes in operating speeds and acceptable accident rates are suggested and various nomographs developed to evaluate consistency or inconsistency of roadway sections based upon their design parameters.