Insights into driver adaptation to inclement weather in Canada

This study explores driver adaptation to inclement weather at two temporal scales. The first part of the paper asks whether drivers become acclimatized to weather conditions. This issue is addressed using data for 23 Canadian cities, based on the relationship between exposure to rain, heavy rain, snow, heavy snow, and icy pavement conditions vis-à-vis the risk of collision. The results do not provide strong evidence that drivers become acclimatized to local weather patterns, which underscores the need to look at driver adaptations on shorter time scales with a view to identifying situations or driver groups where risks are particularly elevated. The second part of the paper focuses on the issue of speed – both from the perspective of posted speed limits, and also in terms of driving speeds. The focus is narrowed to one part of Canada and to winter-weather conditions. The risk analysis confirms that days with snow, freezing rain, or other frozen forms of precipitation have elevated collision rates; and it provides evidence that relative risk is higher in rural areas than in nearby cities. The analysis also suggests that collision rates increase as the posted speed limit increases. These findings further highlight the importance of driving speed in weather-related collision occurrence, and that driving above posted speed limits occurs even during inclement weather.