Accidents at Urban Mini-roundabouts
KENNEDY ,IV, Transport Research Laboratory, HALL R D and BARNARD SR, Southampton University, UK
Mini-roundabouts have been used extensively at urban j6netions since their introduction in the early 1970's. They have central islands of up to 4m in diameter, which have no street furniture and are capable of being driven over;, they are generally subjec
Mini-roundabouts have been used extensively at urban j6netions since their introduction in the early 1970's. They have central islands of up to 4m in diameter, which have no street furniture and are capable of being driven over;, they are generally subject to a 30 mph speed limit. In 1994, approximately 1,400 personal injury accidents occurred at mini- roundabouts. Although these numbers are relatively low and there are only a small number of these junctions compared with other junction types, their numbers are increasing rapidly. Therefore it is important that they are designed to be safe. The number of mini- roundabouts was estimated to be about 1600 in the year 1988 and predicted to be about 2500 by the year 1994 as priority junctions were converted to mini-roundabouts and traffic calming became more widespread (Summersgill, 1989; Walker and Pittam, 1989).
This paper outlines some of the results from a recent study of accidents at 3-arm and 4-arm mini-roundabouts on two-way slngle-carriageway roads in built-up areas (Kennedy et al, 1997). The aim was to determine how accident frequency is related to vehicle and pedestrian flows and to the layout and features of the junction. It was undertaken on behalf of the Road Safety Division of the Department of Transport (DOT) by the Transport Research Laboratory (TRL), with the University of Southampton as a sub-contraetor. Accident predictive models have been developed using generalised linear modelling techniques.
The study is one of a series investigating accidents at different junction types including: 4-arm small island and conventional roundabouts (Maycock and Hall, 1984); 4-arm urban traffic signals (t/all, 1986); urban T-junctions (Summersgill et al, 1996); 3-arm urban tra:lfie signals (Taylor et al, 1996); and 4-arm urban priority junctions (Layfield et al, 1996).
Association for European Transport