Citation

Wood G, Turner S, Roozenburg A. Proc. ARRB Group Bienn. Conf. 2006; 22(CD-ROM).

Affiliation

Macquarie University; Beca Infrastructure

Copyright

(Copyright © 2006, ARRB Group)

DOI

unavailable

PMID

unavailable

Abstract

The management of speed is considered an important safety issue at roundabouts.  The approach speed and negotiating  speed through roundabouts depends on both the geometric  design of the roundabout and sight distance.  In New Zealand  and in the Australian States the design standards (based on  Austroads) recommend long approach sight distance and  provision of relatively high design speeds.  This is in contrast to  European roundabouts where visibility is normally restricted and  the geometric design encourages slow approach and  negotiation speeds.  The earlier 'flow-only' models (models with  only flow predictor variables) have been extended to include  non-flow variables, such as sight distance, intersection layout  and observed speed variables.  Models have been produced for  the major motor-vehicles only, pedestrian versus motor-vehicles  and cyclists versus motor-vehicle accident types.  'Flow-only'  models have also been produced for roundabouts on roads with  high speed limits.  The models have then been used to assess  whether a move towards the European design philosophy, of  lower speed and reduced sight distance, may lead to lower  accident rates for all modes, particularly in areas that have high  concentrations of pedestrians and cyclists.