Towards Linking Climate and Weather Phenomena to Road Safety Outcome Part 3 of 3: Short-term influences of weather patterns

Abstract

This paper is the last of a three-part series. Part 1 identified the breadth of weather factors collectively contributing to crash risk and consolidated relevant research. Part 2 illustrated the cyclic nature of climate, weather, and crashes and how they vary over time. In part 3, the differences in weather conditions on days with high and low casualty crash numbers, days with high fatal crash numbers, and long sequences of days with and without fatal crashes were analysed using readily available Bureau of Meteorology (BOM) metrics: maximum and minimum daily temperature, daily rainfall, 6-hour synoptic charts, daily solar radiation, and water vapour pressure (for 9am and 3pm). The results showed marked differences between high and low casualty crash days. Spatial distributions of daily crashes show alignment with the movement of weather patterns across Victoria as observed in synoptic charts, particularly in relation to low pressure systems and troughs, likely duration of damp pavement conditions and periods of extreme heat and cold (well above or well below average for that time of year in that location). Understanding how specific climate and weather events can influence crash risk may help develop additional strategies to improve road safety and reach the target of zero deaths.