Traffic analysis zone

From Freepedia

A traffic analysis zone is the unit of geography most commonly used in conventional transportation planning models. The size of a zone varies, but for a typical metropolitan planning software, a zone of under 3000 people is common. The spatial extent of zones typically varies in models, ranging from very large areas in the exurbs to as small as city blocks or buildings in central business districts. There is no technical reason why zones cannot be as small as single buildings, however additional zones add to the computational burden.