A city that outdistances man's walking powers is a trap for man.

Toynbee’s line warns that when urban scale and design exceed what an ordinary person can traverse on foot, the city stops serving human needs and begins to constrain them. A walkable city allows residents to reach work, shops, civic life, and one another through their own bodily powers; once distances sprawl beyond that, daily life becomes dependent on vehicles and infrastructure that not everyone can access equally. The “trap” is both practical and moral: people are locked into time-consuming commutes, social segregation, and a built environment that prioritizes speed and throughput over community, health, and public life. The remark anticipates later critiques of automobile-centered planning and the loss of human-scale urbanism.