GEOMETRIC DESIGN OF ROUNDABOUTS IN POLAND - RECENT YEARS' EXPERIENCE

In the post-war period, Poland's road design practice did not account for roundabouts, even though many European countries, mainly the UK and France, chose this as a commonly used type of junction. Following the dramatic road safety decline, roundabouts have been recognised in Poland as an alternate to signalization and an effective road safety measure. Published in 1996, Roundabout Design Guidelines (Tracz et al., 1996) triggered the use of roundabouts and helped to provide a uniform, and technically justified, approach to selecting the geometric parameters of roundabout design. It is now possible to evaluate the roundabouts built, in terms of their safety, operational effects, the choice of geometric parameters and observance of the guidelines. The specifics of Poland's roads and road traffic (hardly any road network hierarchization, mixed traffic, etc.) requires a thorough analysis of data on the location of the roundabout being designed. The paper presents an evaluation of the respective design practice based on about a dozen roundabouts that have been recently built in Poland. A recommendation as to further implementation of roundabouts on urban and rural roads is given. The paper presents the effects that the applied geometric solutions have had on road safety (road accidents, traffic conflicts), speed of traffic on roundabouts and traffic capacity.