Analysis and Comparison Between Two-lane Roundabouts and Turbo Roundabouts: Based on a Road Safety Audit Methodology and Microsimulation—A Case Study in Urban Area

Turbo roundabouts are a type of intersection with an increased use in Holland during the last ten years, and since its invention in 1996, more than 130 of these have been built in this country. Recently, one was built in Germany and three in Spain. A field study has shown that turbo roundabouts have helped reduce accidents by a significant 80% in comparison to intersections regulated by roundabouts. In the same way, its new geometry has restricted weaving and persuaded drivers on the road to yield to a maximum of two lanes, providing an additional capacity of 12% to 20% of the rotating roadway. In order to implement the first turbo roundabout in Bogota, a research was developed to compare the two-lane roundabouts and basic turbo roundabouts to different aspects of capacity, level of service, and road safety. During this research, micro simulation was used to determine the performance of road capacity by implementing a basic turbo roundabout as a control mechanism within an intersection, currently regulated by a conventional roundabout. The benefits in relation to road safety and traffic indicators were analyzed to allow a feasible implementation of these new intersections, generating a preliminary design criterion that can be reevaluated. To compare the two types of intersections in terms of road safety, a methodology of road safety audits (RSA) is proposed and applied.