Abstract
The COVID-19 pandemic has upended how people travel
and how transportation systems function. Travel is down
across all modes in 2020, though the declines on public
transit have been greater and the recovery slower than on
other travel modes, such as private automobiles and “active”
transportation modes like biking and walking. This shift in
travel mode choice away from transit is likely explained at
least in part by would-be riders’ fears of infection during
this communicable disease outbreak because public transit
congregates people in dense and enclosed environments.
To lower the risk of infection and reduce the spread of
COVID-19, transit agencies worldwide have implemented
measures such as route and service modifications,
improved ventilation and air filtration, increased cleaning
and disinfecting, modifications of seating and boarding
protocols to ensure physical distancing, mask-wearing
requirements, and even screening riders for fevers.
The perception that public transit poses an elevated risk
for the transmission and spread of infectious diseases
influences both people’s reluctance to ride and transit
agencies’ various pandemic response measures. But is
this perception merited, and is transit “safe” to ride? Since
the beginning of the COVID-19 pandemic, this question
has been widely debated. But this is a complex issue that
defies a simple “yes” or “no” answer, as it depends on many
factors (such as ambient infection rates) beyond transit
operators’ control. As we found in our review of the public
health literature, the relative infection risk on public transit
depends not only on how transit operators respond, but
also on the particulars of the communicable disease, rider
and employee adherence to public health guidance, the trip
durations and densities of riders on vehicles, as well as the
effectiveness of the broader public health response. Thus,
arguing in the abstract about whether riding transit is safe
or dangerous during a pandemic is a bit like arguing about
the area of a rectangle knowing only the length of one side.
