Bus Rapid Transit, Safety, and Roundabouts: Evaluation of design solutions for roundabouts with Bus Rapid Transit based on safety and level of service of all modes

• Main Author: Hafsteinsdóttir, Gudrun Birta (author)
• Other Authors: van Nes, R. (graduation committee), van Oort, N. (graduation committee), Farah, H. (mentor), Skarphéðinsson, Albert (mentor), Delft University of Technology (degree granting institution)
• Format: Master Thesis
• Language: English
• Published: 2022
• Subjects: Bus Rapid Transit; Roundabout; Safety; Throughabout; Evaluation; Microsimulation; Centre Island; Lanes; Iceland
• Online Access: http://resolver.tudelft.nl/uuid:8bd51dbe-19d7-4e0e-8b29-4d4bda095f78

The popularity of Bus Rapid Transit (BRT) has been growing rapidly over the past years, where more and more cities add BRT to their public transport systems. Roundabouts are also growing and are popular intersection designs because they are one of the safest types of intersections and improve traffic flow. It is, therefore, likely that in some cities a BRT route will go through a roundabout. To keep the priority of BRT and the safety effects of a roundabout, the evaluation of roundabouts with BRT based on safety and level of service (performance) of all modes is investigated. Some countries have already developed and built solutions for roundabouts with BRT, where the priority of the buses can differ. One solution, often called throughabouts, is where the exclusive bus lanes go through the centre island of the roundabout, giving full priority to the buses. However, few guidelines have been developed on roundabout solutions with BRT and there seems to be a disagreement about the effectiveness of these types between some countries. This thesis aims to reduce this research gap by developing an evaluation methodology that compares and evaluates different design solutions of roundabouts with BRT based on the safety and level of service of all modes. The evaluation methodology is also able to determine which design solution is the most optimal. The methods used to compare and evaluate the designs in the methodology are literature review, multicriteria analysis (MCA), microsimulations and calculations, and a case study. A case study of a roundabout in Reykjavik, Iceland is used to illustrate and test the methodology. Three design solutions are compared and evaluated where the priority configuration of the BRT is changed for each design. Design 1 is a regular roundabout where the buses drive through the intersection in mixed traffic. Design 2 is a throughabout where there are traffic signals for all entering traffic, and design 3 is a throughabout where there are traffic signals for the conflicting traffic. These ...