Housing and land use

A rezoning is on the table, or a new transit line, and someone wants to know what the city will look like in twenty years because of it: how many homes, where, at what price, and who moves.

What you are really asking

Land use and travel are coupled. People choose where to live partly by how they can get to work; developers build where people can get to; both change what the roads and trains carry. So the question is really: what does this change do to the whole loop, over years? Beneath it are the questions the council will actually argue about: how many homes, how affordable, how much traffic, and what it does to the tax base.

What kind of model answers it

An urban simulation model represents households, jobs, buildings and land parcels and lets them change year by year under rules about development and location choice. It is usually run beside a transport model so that travel times feed back into where people choose to live. The outputs are maps of development and population by year under each scenario, which is what the question wants, and they are only as good as the assumptions about how people and developers behave, which the model should state.

On this site, UrbanSim is the open model of this kind, and Urbanly CityCompass a hosted one. Each links back here.

What you need

• Parcels and zoning, from the city.
• Where people and jobs are now: in the United States, the Census APIs.
• The street and transit network, usually starting from OpenStreetMap.
• A written description of each scenario, agreed with the people who will argue about the results.

Without a model

Count the parcels the rezoning touches and what the new rules allow on each. That arithmetic is the upper bound on what can happen and is often most of the answer. Ask who did a similar rezoning nearby and what was built.

Next

Name the question and Talk to the people affected, because this question is argued, not solved.