Tracing long-term commute mode choice shifts in Beijing: four years after the COVID-19 pandemic

The COVID-19 pandemic has brought urban mobility into a new era. This study traces post-pandemic shifts in commute mode switch behaviors and their environmental effects based on an event study design and a mobile phone signaling dataset for Beijing from April 2018 to November 2023. The results show that in the outbreak stage, public transit mode share nosedived, with transit riders 5.11 and 3.75 times more likely to switch to private car and active modes, respectively; in the post-pandemic stage, public transit recovered rapidly and to a large extent, but the increase of private mode dependency persisted, as transit riders were 1.88 times more likely to switch to private cars, and transit riders and car drivers were 1.37 and 1.32 times more likely to adopt active modes, respectively; in the pandemic-free stage, signs of private car dominance began to emerge, as driving habits strengthened and more active travelers resorted to driving, indicating the closing of the window of opportunity to promote low-carbon private transport. This study presents the longest longitudinal tracking of post-pandemic travel mode choice so far. The challenges and opportunities faced by the transportation system are discussed, and policy implications and future research directions are provided.