To achieve safe and unobstructed traffic flow at roundabouts and their approaches, the important condition that needs to be met is adequate visibility. Namely, a clear line of sight must be ensured to enable a driver without the right of way to engage in the roundabout traffic flow safely and to note on time the position of the vehicle in front of him. The issue of sight distance evaluation on suburban single-lane roundabouts will be analysed in this paper. A critical review of several roundabout design standards and guidelines (Australian, Croatian, and Italian) that describe procedures for determining the necessary sight distance at these intersections will be given. Influential parameters for defining clear sight areas will be presented in detail, with an emphasis on the diversity of roundabout sight distance evaluation approaches. Key issues of the existing Croatian guidelines will be identified, and recommendations for the improvement will be given. Test results obtained on a theoretical example of a suburban roundabout will also be commented on.

sight distance; design guidelines; recommendations