The Girl on the Bus: Familiar Faces in Daily Travel and Their Implications for Crime Protection

Hägerstrand proposed that individuals’ daily mobility is constrained to a particular time–space path by capability, coupling, and authority requirements. This tethering of routine activities to particular places at scheduled times facilitates repetitive bundling of individuals at certain nodes. Associations emerging from repeated, cursory encounters between individuals have been coined familiar strangers. “Familiar strangers” is a unique social phenomenon that emerges where individuals experience repeated visual encounters but never verbally interact. Scholarship suggests that increased familiarity among individuals might incur social benefits at places by reducing individual anonymity and enhancing the moral obligation to obey behavioral norms, which in turn could have a crime protection effect. In this study we spatially and temporally integrate a large smart card data set with a database of crime incidents along with census information to examine the relationship between bus stops with varying concentrations of familiar strangers and the occurrence of three crime types (theft, drug, and nuisance offenses). The findings demonstrate the potential for familiar strangers to provide crime guardianship at bus stops and also highlight the influence of surrounding land use and neighborhood sociodemographic environment on crime risk.