Understanding the Impacts of Weather and Climate Change on Travel Behaviour

Detta är en avhandling från Stockholm : KTH Royal Institute of Technology

Sammanfattning: Human behaviour produces massive greenhouse gas emissions, which trigger climate change and more unpredictable weather conditions. The fluctuation of daily weather corresponds to variations of everyday travel behaviour. This influence, although is less noticeable, can have a strong impact on the transport system. Specifically, the climate in Sweden is becoming warmer in the recent 10 years. However, it is largely unknown to what extent the change of travel behaviour would respond to the changing weather. Understanding these issues would help analysts and policy makers incorporate local weather and climate within our policy design and infrastructure management.The thesis contains eight papers exploring the weather and climate impacts on individual travel behaviour, each addressing a subset of this topic. Paper I explores the weather impact on individual’s mode choice decisions. In paper II and III, individual’s daily activity time, number of trips/trip chains, travel time and mode shares are jointly modelled. The results highlight the importance of modelling activity-travel variables for different trip purposes respectively. Paper IV develops a namely nested multivariate Tobit model to model activity time allocation trade-offs. In paper V, the roles of weather on trip chaining complexity is explored. A thermal index is introduced to better approximate the effects of the thermal environment. In paper VI, the role of subjective weather perception is investigated. Results confirm that individuals with different socio-demographics would have different subjective weather perception even given similar weather conditions. Paper VII derives the marginal effects of weather variables on transport CO2 emissions. The findings show more CO2 emissions due to the warmer climate in the future. Paper VIII summaries the existing findings in relations between weather variability and travel behaviour, and critically assesses the methodological issues in previous studies.