Passerbys

Passerbys are people who pass by a particular place or event, usually pedestrians moving through a public space who are not directly participating in or responsible for the activity at hand.

The term is used in everyday speech and in reports to denote observers or witnesses who are not involved in the incident. Singular: passerby; plural: passersby or passers-by.

In urban planning and safety contexts, passersby are a key component of street life and pedestrian safety; designers study their movements to improve crosswalks, signage, and lighting.

In research on social behavior, passersby can be subject to the bystander effect, wherein individuals are less likely to help when others are present; this has informed policies on crowd management and emergency response.

In reporting and literature, passersby are commonly cited as witnesses; their accounts are often used to describe events without asserting involvement.