| The concept of design consistency is one of several tools used by highway designers to improve roadway safety. The most promising consistency measures identified in previous research fall into four main categories, namely: operating speed, vehicle stability, alignment indices, and driver workload. Previous research has focused on the development of models that can estimate these consistency measures, while little research has considered their relationships to safety. The main objective of this thesis is to quantify the relationships of individual consistency measures to actual collision experience through regression analysis. A subsequent objective is to provide an overall safety-based model for consistency evaluation. Model development was based on a database consisting of 70 horizontal curves located on two-lane rural highways in Eastern Ontario. Several statistically significant models relating the consistency measures to safety were developed. These models provide a quantitative tool for evaluating the safety benefits of improving the consistency of design elements. |
