Abstract
Coronavirus disease 2019 (COVID-19) has had a disruptive impact on transportation. To prevent a return to more widespread personal automobile use due to social distancing requirements, public transport should regain its critical role in carrying a large number of passengers. To this end, three Chinese cities, Hangzhou, Ningbo, and Xiamen, implemented fare-free policies to lure passengers back to public transport. To capture the effect of these policies implementation on the daily subway passenger flow, a synthetic control method is used to construct a counterfactual outcome of interest for these three cities. The results show that the peak-hours free-ride policy in Hangzhou had no significant effect on subway ridership, the "more rides, more discounts" and off-peak-hours free-ride policies in Ningbo increased subway ridership by about 24% in the first month, and a rest day free-ride policy in Xiamen increased subway ridership by 2.3 times over five rest days. Nevertheless, the role of the fare-free policies in helping subway ridership rebound to the historical levels is limited, whether it is during or after policy implementation. Findings of the current study can inform the local authorities and transport operators that the multi-pronged approaches should be implemented in tandem with the fare-free policies for increasing subway attraction during the recovery phase of the COVID-19 pandemic.