A model of underground ridership during the severe outbreaks of the SARS epidemic in a modern city

TL;DR

This study models how underground ridership in Taipei decreased during the 2003 SARS epidemic, showing a direct correlation between reported cases and ridership decline with a decay over time.

Contribution

It introduces a quantitative model linking SARS case reports to underground ridership decline, capturing the dynamics of public response during an epidemic.

Findings

Each SARS case causes an immediate ridership drop of about 1200.

Ridership loss decays with an e-folding time of approximately 28 days.

Ridership decreased by about 50% at the peak of the SARS outbreak.

Abstract

The outbreaks of the severe acute respiratory syndrome (SARS) epidemic in 2003 resulted in unprecedented impacts on people's daily life. One of the most significant impacts to people is the risk of contacting SARS while engaging daily routine activity. In this work we use data from daily underground ridership in Taipei and daily reported SARS cases in Taiwan to model the dynamics of the public underground usage during the wax and wane of the SARS period. We found that for each reported SARS case there is an immediate loss of about 1200 underground ridership. These loss rates propagate to the following days with an e-folding decay time of about 28 days, reflecting the public perception on the risk of contacting SARS disease when travelling with the underground system. About 50% of daily ridership was lost during the peak of the 2003 SARS period, compared with the loss of 80% daily ridership during the closure of the underground system after Typhoon Nari, the loss of 50-70% ridership due to the closure of the governmental offices and schools during typhoon periods, and the loss of 60% daily ridership during Chinese New Year holidays.