The impacts of extreme hot weather on metro ridership: A case study of Shenzhen, China

Under climate change, cities around the world would be faced with increasingly frequent, intense, and prolonged heatwave events. Currently, not enough research has looked into the temperature-metro ridership relationship in the scenario of extreme hot weather. Moreover, a geographical perspective, particularly on the characteristics of the built environment surrounding the metro stations, is still lacking in existing studies. To fill these research gaps, this study uses one year of hourly metro ridership and temperature records to examine the general relation between temperature and metro ridership. It also further investigates the metro ridership change during a weeklong heatwave event in Shenzhen in 2016. Multivariate regressions were built for the overall scenario and separately for the weekday, weekend, peak hours, and off-peak scenarios. The results provide evidence for the non-linear relationship between the rise in temperature and the increase in metro ridership. The findings also suggest a general decline in metro ridership both on weekdays and the weekend during the heatwave, with more remarkable change observed on the weekend and off-peak hours on weekdays. Urban environment characteristics around metro stations, such as the number of companies, population density, amount of tree canopy, as well as the betweenness-centrality of stations, are found to be associated with the magnitude of change in metro ridership during the heatwave. The findings of this study offer some implications for the planning, design, and operation of metro systems in the future.