A Method for the Landscape and Environmental Impact Evaluation of Roundabouts

The interest of researchers and practitioners on roundabout solutions for level intersections has been growing increasingly in the last decades and this has stimulated new paradigms for performance evaluation. The often larger areas occupied by this type of intersection, both in a rural and in an urban environment, require special attention on the use of ground and the preservation of the natural, environmental and architectural heritage and also present the opportunity for evaluating their impact on the landscape and environment. The paper proposes a new method for evaluation borrowed from building technology and based on the needs, requirements and performance expected from an object rather than on prescriptions for and descriptions of its dimensions and quality. The method has been developed taking into consideration especially European (and, more specifically, Italian) experiences but results and conclusions can be considered as general. After a synthetic glossary of the specific language and approach used, the paper provides a series of data to be collected in order to achieve the roundabout evaluation: the list of the classes of needs, requirements and performance on which evaluation is based; the basic geometrical/functional/material elements into which to break down the roundabout; the relationships between classes and basic elements. Standard sheets on which roundabout data can be collected are also prepared. Finally a complete evaluation sheet is provided.