Psychological stress of bicycling with traffic: examining heart rate variability of bicyclists in natural urban environments

•The local road showed lower bicyclist stress compared to collectors and arterials.•Collectors showed lower bicyclist stress compared to the arterials but with large uncertainty.•The ability of HRV to measure psychological stress while bicycling is possible but uncertain. Understanding how road environments stress bicyclists (and prospective bicyclists) has important implications for road design and network planning. With the rise of wearable bio-sensing technology, the potential for measuring real-time environmental acute stress is emerging. In this naturalistic cross-over field experiment, we investigate bicyclist stress through heart rate variability (HRV). We examine the relationship between HRV and the road environment through a series of multilevel statistical models. Results suggest that participants’ HRV are only certain to differ on one (the local road) of five road environments tested. The differences in participants’ HRV between two collectors and two arterials are far more tenuous. We discuss the validity of HRV and other biometrics for assessing stress and discuss how HRV and other biometrics might help improve our understanding of bicyclists’ perceptions of road environments.