Explaining Form-Based Zoning

Riverfront Crossings will lead to some big changes in Iowa City, and the crux of the development is form-based zoning. Form-based zoning isn’t common and is a big departure from how we usually zone municipalities. As of April 2013, only about 300 places had adopted form-based zoning across the country. That’s just 0.2 percent of U.S. cities. Let’s take a closer look at form-based zoning and what it means

Zoning is how governments organize where stuff can be put in a city. Usually zoning is use-based and mostly organized into three major categories: residential, commercial and industrial. A city will say that on this chunk of land you can build houses, on another you can build stores and offices, and on another you can build factories and plants. A cities land is organized by how the city wants it to be used.

Form-based zoning is basically the opposite of used-base zoning. Form-based zoning focuses on how the built environment will look, not the specific use of each plot of land. Here’s a good definition from the Form-Based Codes Institute:

“Form-based codes address the relationship between building facades and the public realm, the form and mass of buildings in relation to one another, and the scale and types of streets and blocks.”

It can be hard to visualize what form-based zoning means. Take a look at this (short and silent) video from the Form Based Zoning Institute that gives a good overview of form based zoning goals.

Form based zoning is use agnostic,for the most part. Instead of zoning by land use, you use zoning as a tool for neighborhood creation. This is a form of placemaking, or designing parts of a city in a way that makes them useful for people rather than cars.

The Pedestrian Mall in downtown Iowa City is an example of placemaking. So is the NewBo Market Square in Cedar Rapids. The pop-out patios in downtown Cedar Rapids and Iowa City are small-scale examples of placemaking.

Riverfront Crossings has plans for a park, plaza and improved spaces for pedestrians and cyclists. All are examples of placemaking. What makes Riverfront Crossings really interesting is how it accounts for how buildings relate to these spaces and each other — that’s where form-based zoning comes into the picture.

Let’s pull out the separate parts from the definition I gave you and take a look at how Riverfront Crossings uses them. All the renderings below are taking from the Riverfront Crossings Master Plan.

First up, “form-based codes address the relationship between buildings and the public realm.”

‘Public realm’ refers to spaces like parks, plazas and streets. Form based zoning makes sure that buildings have windows and doors that face onto these public spaces and are easily accessible.

One of the things that can kill pedestrian activity are stretches of dead space. Long areas of blank walls, vacant lots or parking lots can make pedestrians feel unsafe and uncomfortable walking through an area. If an area is trying to encourage pedestrian activity, it has to make sure to keep these pedestrians feeling safe and give them a reason to walk, rather than drive. In Riverfront Crossings, specific intersections and streets will require retail space along the ground floor of a building, so if you’re walking there will always be a nearby destination. Buildings will be built so that they ‘face’ the street, meaning that you won’t encounter a block-long blank wall along a sidewalk. Parking will either be along the street — which makes pedestrians feel safer because it creates a barrier between traffic and people — tucked behind buildings, or in parking garages.

Next up: “form-based codes address… the form and mass of buildings in relation to one another.”

Really, mass and form are just fancy ways of saying size and shape. Form-based zoning tries to make sure that the size of a building makes sense compared to the building next door, for the volume of traffic of the road, and for the specific goals a city has for a street or area.

Finally, “form-based codes address… the scale and types of streets and blocks”

Streets are public spaces and need to be able to be as useful to people as they are to cars. There are high traffic streets and low traffic streets, wide streets and skinny streets, quiet residential blocks and busy retail blocks. Each one is important and serves a role in making a neighborhood. Take a look at this rendering of busy Gilbert Street from the Riverfront Crossings Master Plan:

Wow! There’s a lot going on here. Four traffic lanes, bike lanes, parking, three banks of trees, and wide sidewalks. This is a 114 feet wide, high-volume street with stores and offices that needs to be made comfortable for people while still handling a lot of traffic.

Now take a look at a “general residential” street:

There are quite a few differences. Only two lanes of traffic and no median, skinnier sidewalks with more green space, and no dedicated area for biking. In total it’s only 80 feet wide.

These two streets are designed to handle very different amounts of traffic and people. The scale, the size of the right-of-way, and the amount of stuff (bike lanes, medians) are dependent on the needs of a particular street or a particular block. Form-based zoning makes sure that the different kinds of streets and blocks in a neighborhood have a plan for how they should be organized.

This is just a general introduction to some of the main concepts of form-based zoning. The Form-Based Codes Insititute believes buildings and public spaces should be thought of together. How tall or wide buildings are should depend on their neighbors and adjacent public space. Streets should be designed as public spaces, useful for people, and have different stuff for different uses. All of these concepts should be used in conjunction with each other to create a place that is attractive, vibrant and has many uses.