Understanding the influence of weather and warning information on trip and activity decisions, behaviour, and risk outcomes
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Winter storms present challenges to the safe design, operation and maintenance of transportation systems. Weather warning information, often originating from publicly funded meteorological services, is intended to support decision making in ways that reduce risk and disruption. Among the general public, the most frequent weather-sensitive decisions are those associated with personal mobility—routine trips that serve or facilitate social interaction, employment, business, shopping, recreation and leisure activities. While existing research examines hazard perceptions, driver adjustments, and the effects of weather on mobility and safety outcomes, few studies have explicitly investigated how weather and related warnings affect trip and activity decisions and behaviour, and risk outcomes, during winter storms. Gaps in the literature remain regarding: non-auto modes of winter mobility; dynamic aspects of individual hazard perception, information use, and trip and activity behaviour; effects of research design, method and measurement choices on insights about warning efficacy; and the applicability of current behavioural theory to enhance understanding. These concerns were addressed in this dissertation using a mixed-methods approach that included: formal risk analysis of large secondary motor vehicle collision and fall injury data sets; semi-structured interviews with a purposive sample of households with high levels of everyday travel; experience sampling of the same cohort during multiple winter storms in near real-time; and analysis, evaluation, and interpretation of the Theory of Planned Behaviour. The research resulted in several important empirical findings, theoretical considerations, and methodological contributions. Empirical analyses showed that falls account for a greater proportion of the excess injury burden during winter storms than motor vehicle collisions. Further, no official government warning was issued in almost two-thirds of winter storm events that produced excess injuries. The interviews and winter storm surveys exposed more nuanced and detailed interpretations of factors thought to affect trip behaviour, including variable definitions and perceptions of winter storm hazards and a complex arrangement of elements that comprise concern. Empirical findings also supported a role for official warnings in raising participant awareness and increasing confidence in general storm expectations and concern, but highlighted people’s reliance on informal sources to inform specific mobility intentions and behaviours as a storm progressed. vi This dissertation is among the first to incorporate and evaluate a general behavioural theory—the Theory of Planned Behaviour (TPB)—to help explain the influence of weather information on trip and activity practices during winter storms. An interpretive analysis raised questions about the effectiveness of guidance offered through TPB, diagnosing a particular inability of the model to accommodate and discretize potential interaction, sequencing, or substitution among certain protective behaviours. Other contributions of the dissertation were methodological. They included development and successful application of new event definition criteria to capture the entire life cycle and evolution of discrete winter storms as might be perceived and experienced by the public; the design of a consistency analysis method to assess and interrogate TPB constructs using small samples; and the combination of pre-season interviews with a novel experience sampling procedure used to examine inter- and intra-storm effects, which shed unique light upon dynamic aspects of factors and TPB constructs thought to affect the influence of winter weather-related risk information on trip and activity behaviour. The multiple dimensions of temporal and within-participant variation in risk outcomes, exposure, beliefs, perceptions, and preferences revealed through this dissertation strongly points to a future of warning services that necessarily must be tailored to individual situations and circumstances at discrete points in time in order to increase efficacy and societal value.
Cite this version of the work
Brian N. Mills (2021). Understanding the influence of weather and warning information on trip and activity decisions, behaviour, and risk outcomes. UWSpace. http://hdl.handle.net/10012/17371