Assessing the impact of three intersection treatments on bicyclist safety using a bicycling simulator.

Bicyclist safety at urban intersections is a critical element for encouraging an increase in bicycle commuting. With cyclist injury and fatality rates rising due to collisions with vehicles at signalized intersections, increasing the safety of riders continues to be an important consideration when promoting this mode of transportation. Previous research has addressed crash causality and helped to develop several roadway treatments to improve bicyclist safety, but little has been done to compare and contrast the benefits of the various treatment types. This bicycling simulator study examined the impacts of three different intersection treatments (i.e., bike box, mixing zone, and bicycle signals) to better understand their influence on bicyclists' comfort, levels of stress, and riding behaviors. This improved understanding allowed researchers to make recommendations for which of the three designs proved to be most effective for reducing the risk of vehicle-bicycle collisions at signalized intersections. Forty participants successfully completed the study by responding to twenty-four scenarios while riding in the Oregon State University Bicycling Simulator. Time-space measurements revealed that the mixing zone treatment correlated with the most unpredictable riding behaviors. Analysis of the participants' eye-movements revealed a lower rate of recognizing the conflict vehicle when traversing the bicycle signal treatments. Galvanic Skin Response measurements were used to measure participants stress levels but found no statistically significant results, although it was found that the mixing zone elicited slightly larger stress responses. Researchers found the bike box design to be the most versatile, providing a balance of increased safety while also requiring the participant to perceive potential danger and be ready to respond accordingly. The results of this research can provide a better understanding of how to best implement these intersection treatments to increase bicyclists' safety at signalized intersections.