An analysis of turbo roundabouts from the perspective of sustainability of road transportation

Abstract

The designs of turbo roundabouts vary among countries and undesirable and potentially dangerous situations can occur for vehicles passing through the roundabout. In this article, we focus on an analysis of one of the problems within sustainable road transportation, i.e., the geometric layout of turbo roundabouts. First, we review the Czech and foreign regulations and describe the design procedures for turbo roundabouts. Studies that have been performed in the Czech Republic and abroad (the Netherlands, Slovenia, Poland, Germany, Hungary, etc.) are described. We evaluate the geometric layout of turbo roundabouts, the effectiveness of construction adjustments at the entrance to the roundabout, and an analysis of the physical separation of lanes. We present procedures and methods for measurements and assessments, which are used for evaluating the effectiveness of the geometry of a turbo roundabout. Finally, conclusions for the given hypotheses are given, as well as the importance of geometric elements (shape of the turbo roundabout, physical separation of lanes, the spike, etc.) for the actual passage of vehicles through the turbo roundabout. Furthermore, we discuss how these elements influence the safety of road traffic, the sustainability of road transportation, and the emergence of potentially dangerous situations.