Analysis of Sight Distance, Crash Rate, and Operating Speed Relationships for Low-Volume Single-Lane Roundabouts in the United States

Abstract

This paper explores the relationship between sight distance parameters, crash rates, and operating speeds at low-volume single-lane roundabouts in the United States. The understanding of the interaction of design, operations, and crash performance is a step forward in the development and application of performance-based standards for roundabouts. The specific objective of this paper is to quantify the relationship between crash rates, sight distance parameters, and operating speeds to present an approach to establishing performance-based standards that highway practitioners can adopt in roundabout design. Geometric, traffic, and crash data were collected on 72 approaches to 19 low-volume single-lane roundabouts in six states. The data for these sites were broken into two groups based on the posted speed limit (at