https://www.selleckchem.com/products/CP-690550.html g., tram stops) are not perceived as particularly dangerous. Conclusions Understanding why and where cyclists over- or underestimate the actual crash risk may provide a foundation for the design of safer cycling infrastructures, as well as for promoting cycling as a comfortable mode of transportation.Importance The prognosis of post-traumatic headache is poorly understood. Objective To develop and validate a prognostic model to predict the presence of post-traumatic headache six months after a traffic collision in adults with incident post-traumatic headache. Design Secondary analyses of adults with incident post-traumatic headache injured in traffic collisions between November 1997 and December 1999 in Saskatchewan, Canada (development cohort); and between January 2004 and January 2005 in Sweden (validation cohort). Setting The Saskatchewan cohort (development) was population-based (N = 4162). The Swedish cohort (validation) (N = 379) were claimants from two insurance companies covering 20 % of cars driven in Sweden in 2004. Participants All adults injured in traffic collisions who completed a baseline questionnaire within 30 days of collision. Excluded were those hospitalized >2 days, lost consciousness >30 min, or reported headache less then 3/10 on the numerical rating scale. Follow-up rates for both= 0.8, 95 % CI 0.7-0.8). Conclusions and relevance Clinicians can collect patient information on the eight predictors of our model to identify patients that will report ongoing post-traumatic headache six months after a traffic collision. Future research should focus on selecting patients at high risk of poor outcomes (using our model) for inclusion in intervention studies, and determining effective interventions for these patients.Overtaking cyclists is challenging for drivers because it requires a well-timed, safe interaction between the driver, the cyclist, and the oncoming traffic. Previous research has investig