Influence of weather on aspects of driving behaviour at an urban intersection

Weather conditions increase crash risk due to decreased visibility, changing vehicle dynamics, and driving behaviour. It remains unclear how different weather conditions affect non-crash driving behaviour, whose understanding is essentially important for the genesis of crashes, and for the development of automated driving functions (ADFs). In this study the influence of 25 different weather conditions on driving behaviour at an urban intersection in Germany was quantified using selected surrogate measures of safety (SMoS). For this purpose, eight months of combined trajectory and weather data were used. For each interaction the most critical moments defined by the minimum time-to-collision, and the associated kinematic profiles in that moment were evaluated. The findings suggest measurable and significant differences in driving behaviour across all weather types, indicating that drivers adjust speed, acceleration, and spatio-temporal distances in response to weather, but particularly in response to their manoeuvres. Apparently, these responses have no negative effect on road safety. However, the results extend the current state of the art by quantifying weather- and manoeuvre-related behavioural adaptation in non-crash situations and by identifying potential implications for road infrastructure.