When Do Drivers Yield to Cyclists at Unsignalized Roundabouts?

Abstract

Cycling popularity has shown an increasing trend during the last decades in many cities of Europe and USA because of its environmental and health benefits. However, cyclists are frequently involved in traffic accidents, especially, when they interact with vehicles at unsignalized intersections. There is still lack of evidence and analysis on how such interaction is performed. This paper explores empirical evidence of the vehicle-bicycle interaction on a typical Swedish roundabout, and provides insights into factors influencing car drivers' yielding decisions when they interact with cyclists. The vehicle-bicycle interaction was divided into category groups (Non-Conflict, Conflict, Yield, and Non-Yield) and their speed differences were analyzed by group. Furthermore, a discrete choice model was developed to estimate behavioral aspects of such interactions. The observed data showed a higher and significant speed variation among vehicles, whereas bicycles exhibited lower variation across the groups. The modelling results revealed that the yielding probability decreased when the speed of the vehicle was higher. On the other hand, the bicycle speed had little impact on drivers' decision to yield. More importantly, the yielding probability increased significantly by the proximity of the cyclist to the conflicting zone. The yielding rate of drivers can be improved by keeping vehicles' speed under 20 km/h, as drivers have the capacity to detect and yield to cyclists.

Exploring regional differences in cyclist safety at roundabouts: A comparative study between the UK (based on Northumbria data) and Belgium

“…If a driver's approach speed is higher, their yielding behaviour towards cyclists' decreases. Silvano et al (2015) conversely suggested that cyclist speed has a slight effect on vehicle yielding behaviour. while any increase in vehicle speed causes a sharp decrease in the yielding probability.…”

“…Previous research has been critically reviewed to endorse the research gaps identified and to inform which variables have been found to be important and therefore need to be considered in this research, the results of which are presented later sections of this manuscript. Studies (Rasanen and Summala, 2000;Silvano et al, 2015) claimed that the possible major factors related to cyclist-vehicle collisions might be driver behaviour and yielding problems. 7-15% of drivers were found not to be aware of cyclists approaching from the right (Rasanen and Summala, 2000).…”

“…On the other hand, cyclists are often very confident that vehicles will give priority to them; however, this presumption reduces the safety for cyclists. Vehicle driver behaviour has a strong impact on cyclist position at the roundabout Silvano et al (2015).…”

“…This is a barrier to increasing the number of people cycling and realising the benefits of cycling on health, to the environment and economic perspectives. This issue has been a motivation for previous studies (Hels and Orozova-Bekkevold, 2007;Møller and Hels, 2008;Daniels et al, 2009;Sakshaug et al, 2010;Silvano et al, 2015;Jensen, 2017), which provided recommendations for policy makers and design engineers to improve safety for cyclists. However, there is a difference in design dimensions and human behaviour related factors in each country (Tollazzi, 2015).…”

Drivers’ Braking Behaviors in Different Motion Patterns of Vehicle-Bicycle Conflicts

“…Wood et al [10] found that drivers' attitudes regarding bicycle visibility disagree with those of bicyclists, which also causes the V-B accidents. Silvano et al [11] found that drivers would yield to bicyclists in V-B conflicts at unsignalized roundabouts. Though these researches investigated drivers' behaviors in V-B conflicts, they provided no specific profile of drivers' braking behaviors.…”