ROUNDABOUT SAFETY – INFLUENCE OF SPEED, VISIBILITY AND DESIGN

Roundabout design in New Zealand generally follows the Austroad guideline for intersection design (Austroads, 2005), which recommends long approach sight distances and provision of relatively high design speeds. This is in contrast to European based design philosophy where visibility is normally restricted and the geometric design encourages slow approach and negotiation speeds. This paper reports on the results of a study that used crash prediction models to investigate how the characteristics of roundabouts influences safety at 104 roundabouts in three centres. Using a dataset that contains pedestrian, cyclist and motor vehicle flows, approach and circulating speeds and sight distances an analysis was carried out for a number of crash types and new crash relationships established. It will be shown that safety benefits can be achieved by a more European based design philosophy