Social pandemic? The effect of COVID-19 on familiar stranger encounters in a public transit network

• Covid-19 interrupted patterns of social encounters on transit networks. • Non-obligatory, social encounters important to prevent loneliness. • Social encounters on transit networks did not regenerate within 2 yrs. • Transport policies must adapt to enduring changes in mobility to restore social connections. Familiar strangers, also known as invisible social ties, emerge from shared schedules and socially institutionalised routines that repeatedly bring individuals together in time–space. While unplanned and non-obligatory, these social encounters of repeated propinquity are vital sources of belonging, connection and ontological security. Drawing on four years of disaggregate smart card travel data we employ time series analyses to examine changes in familiar stranger within a public transit environment relations pre-post the onset of covid. We find a sudden and dramatic decline in the volume of repeated social encounters following the onset of the pandemic. Familiar stranger encounters did not return to pre-pandemic levels within the two-year post-pandemic onset captured in our study. Social context is an integral part of the transit experience and plays a significant role in modal choice. Our findings suggest that transport policies that aim to increase public transit ridership should consider how increased temporal and spatial flexibility in everyday obligatory activities (such as tele-commuting) has shifted shared transit routines and, in turn, uncoupled people from their familiar strangers. To support the re-generation of familiar strangers, as a vital source of belonging in the transit community and as an incentive for public transit ridership, we may need to contemplate new ways to encourage time–space co-presence through vehicle and station design, virtual transit chat-groups and/or adjustments to service scheduling.