Hvordan skal smalle dobbeltrettede cykelstier afmærkes? Case: Bryggebroen i København

Abstract

The rise of cycling in Europe offers significant environmental and health benefits, but increasing cyclist volumes present challenges to infrastructure guidelines. With one of the highest cycling rates in Europe, the city of Copenhagen faces significant demands on its cyclist infrastructure. This thesis, developed in collaboration with Copenhagen Municipality, investigates the role of the centreline markings on cyclist be-haviour and safety on narrow, two way cycle tracks. Motivated by a hypothesis from Copenhagen Munici-pality, the study examines whether the centreline acts not as a barrier to maintain proper distance but instead as a focal point that reduces cyclist orientation towards oncoming traffic. The study focuses on Bryggebroen, a narrow two way cycle track bridge where the centreline was recently removed due to maintenance. This thesis assumes that cyclist behaviour on narrow, two way cycle tracks is fundamentally a product of two factors: lateral location on the path and orientation towards oncoming traffic. To investigate this, the study used eye tracking and video recording technologies. The eye tracking study, using specialised eye tracking glasses on four test cyclists, examined their focus on the path centre and oncoming traffic at two similar locations in Copenhagen: Bryggebroen, where the centreline was removed, and Sortedam Dosser-ing, another two way cycle track of similar width and which features a centreline. In addition, the video recording study measured the lateral location of cyclists on Bryggebroen in 25 cm intervals during the morning rush hour. This study was based on a similar 2015 study when Bryggebroen still had a centreline, making it possible to assess the impact of removing the line. In combination, these methods provided a comprehensive assessment of how cyclists' focus and positioning are influenced by the presence or ab-sence of a centreline, offering insights into potential safety improvements. The results from the eye tracking study on the two way cycle track at Sortedam Dossering showed that cyclists tend to focus more on the centreline than on approaching cyclists. Additionally, video recordings from Bryggebroen indicated that after the centreline removal, cyclists were less likely to cross the centreline during overtaking. This behaviour suggests a heightened awareness of maintaining distance from oncom-ing cyclists, potentially reducing collision risks. A notable difference was observed in how much test cyclists focused on the centre area of the bicycle path between the two locations, one with a centreline and one without. These findings demonstrate significant behavioural adjustments depending on the presence of a centreline, highlighting its impact on cyclist safety. A literature review revealed that current guidelines for the width of two way cycle tracks do not account for high traffic volumes like those on Bryggebroen. Additionally, accident and near-miss data from this loca-tion suggest that the bridge may be underdimensioned for current peak cyclist loads. Expanding Brygge-broen's narrow two way cycle track is difficult and expensive within the current structure. However, this study indicates that changes to path markings and railings could enhance cyclist spacing and reduce colli-sion risks. The absence of a centreline positively influences cyclist positioning and orientation towards oncoming traffic. Future studies are needed to fully understand the impact of the centreline markings and its connection to cyclist safety.

A master thesis from Aalborg University

Hvordan skal smalle dobbeltrettede cykelstier afmærkes? Case: Bryggebroen i København

[How should narrow two way cycle paths be marked? Case: Bryggebroen in Copenhagen]