METHODOLOGY FOR EVALUATING GEOMETRIC DESIGN CONSISTENCY

This paper presents a methodology for evaluating and improving the geometric design consistency of rural nonfreeway highways. The methodology is based on driver behavior principles, a sound conceptual approach, and empirical evidence collected during a recent Federal Highway Administration-sponsored research project. Factors that contribute to potential geometric inconsistencies include basic feature type, design attributes, sight distance, separation distance, operating speed, and driver familiarity. The methodology may be applied to proposed or existing two-lane and four-lane highways in flat or rolling terrain. Design speeds may range from 80 km/h (50 mph) to 129 km/h (80 mph). The basic objectives of geometric design and application procedures are presented to aid the engineer in the design or evaluation of a design for geometric consistency.