The speed and configuration of cyclist social groups: A field study

Abstract

Group behaviour is common among bicycle users and can have an impact on traffic dynamics in natural or emergency situations. As our observation shows, 35% of cyclists in traffic ride in pairs or groups. This paper aims to explore how cyclist group members interact and organize in bicycle flow. A field study was conducted, 166 groups of cyclists were selected as the observation objects, and their tracks were obtained through the multi-object tracking algorithm (MOT). The average speed, spatial arrangement and similarity between group members were calculated and analysed. The results show that group size has a significant negative effect on average group speed as cyclist members of the same group tend to maintain similar speeds as they ride forward. The 2-person and 3-person riding groups have relatively “time stable” geometrical structures (4 patterns for pairs and 5 patterns for triads). They are generated not only from traffic rules but also from the local interaction between group members. The dissimilarity value of movement among them tends to increase with increasing group size due to weaker coordination in larger groups. These findings have implications for bicycle traffic modelling and safe bicycle facility design.