The impact of weather on bicycle risk exposure

Abstract

Traffic volume is the main independent variable of risk exposure in road safety models. Cyclists as a vulnerable road users are more exposed to weather conditions than e.g. car drivers. As a result, their decision of whether to cycle is strongly related to weather conditions. It suggests that any change in the weather may have a significant effect on bicycle use. Objective of the paper was to indicate which weather parameters have a significant impact on bicycle use, how a change in weather parameters affects the change in bicycle volume (risk exposure) and, consequently, predicted number of crashes with cyclists and which factors differentiate the impact of weather conditions on bicycle volume. The impact of weather on bicycle volume variability was estimated based on literature review. The Web of Science, Scopus and TRID databases were searched. Finally, 33 papers from 1977 up to 2020, different in terms of the methodology used, country of origin, and analyzed group of cyclists, were reviewed. The impact of change in weather conditions on the predicted number of crashes with cyclists was estimated using own road safety models and previous research results. Results indicate that air temperature, precipitation, sunshine, cloud cover, humidity, and wind strength, have a significant influence on bicycle use. The impact of the weather on bicycle volume differs between different cyclists’ groups (different levels of experience, age, gender), trip motivations (recreational, commuting, etc.) and locations (countries, cities, climate zones). The paper shows complexity of impact of weather conditions on cycling and sensitivity of relationship between weather conditions and bicycle volume (i.e. risk exposure) and, as a consequence, bicycle safety. Results indicate that weather conditions should always be taken into consideration when analyzing cycling, especially in road safety analysis. The discussion of presented research results, research methods used with their limitations, and recommendations for future research were described.