Creating a neighborhood change zoning plan for Spruce Hill

• Philadelphia struggles to provide affordable housing in neighborhoods of opportunity.
•  From  2008 to 2016, the City lost 13,000 lower-cost units - 7,000 between 2014 and 2016 alone.
•  ~34% of  project-based Section 8 units and 20% of all subsidized units will near the end of their affordability restrictions by 2020.
•  9 months  after Philadelphia passed the City's Inclusionary Zoning bonus, only 12 developments were poised to use the incentive.

As demand for land increases -> restrict development -> Price/rents increase

As demand for land increases -> allow development -> Price/rents stabilize

•  Minneapolis : Approved multi-family zoning on all single family zoning lots.
•  Seattle : Upzoned 27 neighborhood hubs surrounding transit areas.
•  California : Continues to push for state legislation to upzone around transit.

( PDF ) Philadelphia is currently considering a bill holding that "no (zoning) variance shall be granted to permit the multi-family use of a property located in certain defined Single Family Preservation Districts, under certain terms and conditions. "

 Down-zoning  has passed or is currently being studied across several neighborhoods.

Too often Growth Coalition politics eclipse the need to preserve the community resources that generate social capital. In addition, profit generated by demolition and new construction often outweigh the need to preserve significant architecture.

Targeting new supply with an eye toward historical & cultural preservation, should foster equity while preserving valuable built environment assets.

1. A community survey is used as an input to a Preservation Index, giving a preservation suitability score to each property.
2. The survey asks residents to rank their Community Preference for where new development should locate relative to amenities like parks and transit.
3. A Development Suitability Index shows which properties are economically feasible to be developed at increased densities, by-right.
4. The overlay of these three indices can help neighborhood residents create a neighborhood zoning plan that balances growth and equity.

The population of Spruce Hill at ~22,000 has barely increased between 2000 and 2020, but rents and home prices have increased (inflation-adjusted) by 25% and 174%, respectively. In the last decade, 76 properties have been demolished while just 85 have filed for a new construction permit. These figures suggest that housing supply has not kept up with housing demand in Spruce Hill.

• A community engagement process surveyed residents on their preference for the preservation of certain buildings in the neighborhood.
• The survey 'experience' is then used (by way of a statistical model) to forecast Preservation Suitability for every parcel in Spruce Hill.

• 60 separate properties were presented in two surveys, from a representative sample (tenure, zoning, age, etc.) of buildings in the neighborhood.
• For each, respondents reported their preference for preservation as either "Strong Preference", "Some Preference", or "No Preference".
• 20 residents at the Spruce Hill Community Association took the survey, resulting in 600 observations of preservation preference.
• Surprisingly, there was some preference for 'No Preservation'.

• Survey responses for 'Strong Preference' and 'No Preference' for preservation were integrated with parcel-level tax and building data.
• A very descriptive predictive model was trained on these responses to estimate a score for each property in Spruce Hill interpreted as the probability community members would have a strong preference for preservation. Below is the predicted index.

The survey also allowed respondents to indicate their preference for where new development should occur relative to amenities.

For each property, the Development Suitability Index reflects how much additional space the current zoning allows if the property were to be developed to a higher density. The index is the percentage increase from the current Total Built Area to the Maximum Buildable Area, given the zoning.

A property with a high Development Suitability Score is suitable for redevelopment by-right (ie. without a zoning variance). The ratio was capped at 1 to indicate that a developer could at least double the built square footage with redevelopment.

1. First, we reveal those properties (in purple) where the Community Preference for development is greater than the Preservation Index. In the map below, the purple parcels are those which community members may be more willing to approve development.

Step 2: Of those the community deems as acceptable for development, properties in purple are economically feasible to develop (without a variance) given the Development Suitability Index. Assuming these parcels reflect the wish of the community (this is a proof-of-concept), the map below could be used to more efficiently communicate development suitability to developers.

We have now identified a set of properties that are:

1. Amenable for development as defined by the community.
2. Economically feasible to develop by-right.

We have also developed a reproducible approach to neighborhood planning using available city open data. With additional refinement, a toolkit can be developed to help other communities replicate our approach.

Future work includes:

1. Building a more diverse coalition of community members to state their preference for both development and preservation.
2. Develop a new index that shows suitability for development with a variance.
3. Work with the local Councilperson to further the community engagement process for actually selecting properties to be up-zoned and to be preserved.

• Will Smith - Dual City Planning/MBA student - University of Pennsylvania
• Fay Walker - Dual City Planning/MUSA student - University of Pennsylvania
• Instructor: Ken Steif, Ph.D - Director, MUSA Program - University of Pennsylvania