How do public transport users adjust their travel behaviour if public transport ceases? A qualitative study

•Explore factors influencing the mode shift to car in the event of a PT disruption.•They are individual-specific, context-specific and journey-specific factors.•Develop conceptual models that structure the PT user’s mode shift process. Mode shift from public transport (PT) to private car when a PT shut-down occurs results in an increase in the number of car trips on the road network which may contribute to traffic congestion. Policies aimed at reducing the mode shift to car can be designed through a better understanding of PT users’ mode shift in the event of a PT disruption. Furthermore, the share of car mode shift is also an important parameter for assessing traffic congestion relief associated with day to day PT provision in cities. This study sought to uncover factors influencing the mode shift to car among PT users in the event of a PT disruption. Semi-structured interviews were conducted with 30PT users from Melbourne, Australia. Grounded theory was used to derive categories and subcategories of behavioural responses. Factors affecting mode shift to car if PT ceases in the short term were classified into three main themes with several subcategories: individual-specific factors, context-specific factors and journey-specific factors. In the long term, the analysis reveals that only context-specific factors have an influence on mode shift. Findings show that car access, travel time, travel cost, trip importance, non-central business district (CBD) trips, weather, flexibility and accessibility to PT stations are the most important factors favouring use of the car if PT ceases in the short term. This acts to increase traffic congestion due to the mode shift to car. However, in the long term, removing PT is expected to have an impact on land use, leading to individuals changing their residential and workplace location.