Comparative analyse of the two new alternative types of roundabouts - Turbo and flower roundabout

Abstract

Alternative types of roundabouts are usually more recent and have been implemented only in certain countries. Typically, they differ from “standard” roundabouts in one or more design elements, whilst the purposes of their implementations are also specific. The main reasons for their implementations are particular the disadvantages of “standard” one- or two-lane roundabouts in particular circumstances or changes of “actual circumstances” which in the past has led to roundabout implementations. Today, several different types of roundabouts are well-known (“mini”, “double mini”, “dumb - bell”, “with transition central island”, “with joint splitter islands”, “traffic signal controlled”, “assembled roundabouts” …), and it is possible to stipulate that they will be further developed in the future. This paper illustrates two relative new alternative types of roundabouts - “turbo” and “flower” roundabouts and their comparison from design, traffic safety and capacity point of view.