Friday, January 18, 2013

Buildout Under Zoning

Have you ever seen a significant real estate subdivision where the parcels are substantially bigger than the minimum allowed by zoning -- where the developer has not tried to maximize profits by selling as many lots and buildings as possible? If you find one, let me know and I will show you ten or a hundred other subdivisions that have maxed out their potential under zoning.

Computing the buildout is an essential first task when considering a zoning change. There are different kinds of buildout analysis, ranging from simple and effective, to complex and detailed.

CommunityViz, is a policy simulator that uses an agent-based model to illustrate the results of land-use policies over time. It is a complex adaptive system that provides a future history of development resulting from deliberate policy choices, such as zoning changes. It will do a sophisticated projection of buildout, for the purpose of comparing the relative effects of different policy choices. Chittenden County Regional Planning Commission (CCRPC) has CommunityViz, data for the entire county, and a staff member (Melanie Needle) dedicated to maintaining data and running simulations.

A direct method of determining buildout under zoning is: Add up the acreage in each zone, then divide by the minimum lot size to get the ultimate number of lots. Then figure out the maximum building intensity on those lots. It can be done on the back of an envelope if you have a good idea of the land areas of each zone type. Note the differences between 'lots', 'buildings', and 'dwelling units' (frequently abbreviated as 'units'). They each have their role in the density calculations.

When computing allowed density, the only deduction from gross land area is for public roads.(ULUDR 2012, Article IX, Section 9.6 A, see below). When buildings from a large project are clustered together, the portion of the gross land area used for roads decreases in significance. For example: (assume all roads are 3-rods [49.5 feet] wide) Take a 32+/--acre subdivision in the Rural Residential district. For 10 3-acre lots @ 250ft of road frontage per lot, 2500ft of road frontage will be needed. With lots on both sides of the road or 1250ft of road right of way. 1250ft*49.5ft/43560square-ft-per-acre=1.42acres for the road -- 4.4% of the total area. But with PRD clustering of the buildings, the lots might shrink to 1/4-acre with about 75ft of road frontage (The standards for the UFVCD). The road necessary road length is only 1/3rd the original, and takes just 0.47acres, or 1.5% of the total area.

Since the Planning Commission's proposal is for straight ahead upzoning, and developers always max out the development potential of a project, buildout under zoning is the obvious choice. But the Planning Commission didn't do any buildout analysis. They didn't even know the size of the new districts that they were creating until long after their second hearing, 11 December 2012. They did not ask CCRPC to simulate the effects of the proposed zoning amendments in CommunityViz.

17 January 2013, Kari Papelbon, Underhill's Zoning Administrator sent me a summary page for the new district areas.

On the summary page, the Range area doesn't quite balance, but because the Selectboard modified the proposal package by removing the Range proposal, I didn't use it when arriving at the estimate of 1000 new residential buildings. It looks like the Range proposal would increase buildout by about (596.2acres-395.6acres)*1lot/3acres=330.6 additional lots in RR, less current 5-acre zoning (60.1acres-78.7acres)*1lot/5acres=-3.7units in WC and 15-acre zoning (3710.66acres-3969.8acres)*1lot/15acres=-17.28units in S&W for a net increase of about 310 lots, or 620 units of permissible (no DRB review for buildings) 2-unit housing. With density bonuses of 100%, the buildout could be 620 buildings.

The buildout under zoning computation goes like this:

The proposed new UFVCD and UCVD districts allow 1/4-acre and 1/2 acre lots respectively. In the Flats: 77.8acres*4lots/1acre=311lots. We need to deduct for the current 1-acre zoning: 77.8acres*1lot/1acre=78lots. In the Center: 88.3acres*2lots/1acre=177lots. We need to deduct for the current 5-acre zoning: 88.3acres*1lot/5acres=18lots. But lots are not units and different maximum densities are allowed in each district: 8units/acre in the UFVCD and 4units/acre in the UCVD. These densities are easily achieved using 2-unit buildings, which are permissible uses (no DRB review necessary). 77.8acres*8units/acre=622 units in the Flats, and 88.3acres*4units/acre=353 units in the Center.

The Flats also contains a new UFVRD district, which has 1-acre zoning, 228.9acres*1lot/1acre=229lots, less the portion of the UVRD district that is currently UFVCD as 1-acre zoning, (228.9acres-77.8acres)*1lot/1acre=151lots, and less the portion of UVRD that is currently 3-acre zoning, 77.8acres*1lot/3acres=26lots. There's a little less precision here because the current UFVCD isn't entirely bounded by the proposed UVRD. These zoning district initialisms are hell, aren't they?

The "Outliers" part of the proposal would convert 156.2 acres of S&W (sorry, it was clipped from the graphic) to RR: 156.2acres*1lot/3acres=52lots, less 156.2acres*1lot/15acres=10lots. 2-unit buildings are permissible, so the buildout would be 42 lots. Again, 2-units are now equivalent to single family homes, so the permissible buildout is 42lots*2units/1lot=84units.

Totaling for net new lots:
 311 lots   Flats  Village Center
- 78 lots
+177 lots   Center
- 18 lots
+229 lots   Flats Village Residential
-151 lots
- 26 lots
+ 52 lots   Otliers
- 10 lots
 486 new lots

2-unit building buildings are permissible everywhere now:

 486lots*2units/1lot=972 new units

If bonus densities are applied at 100%, these could be 972 new separate 1-unit or 2-unit buildings. (ULUDR 2012, Article IX, Section 9.6 A, see below)


Amended March 6, 2012

Article IX Section 9.6 Density Calculations
Calculations of the allowed overall density of development shall be based on total parcel acreage, excluding existing and proposed road‐rights‐of‐way, and lot size and density requirements for the zoning district(s) in which the PRD or PUD is located. This calculation of the site’s overall “yield” shall be used to determine the number of building units or lots that may be clustered or grouped at higher densities on those portions of the parcel that are suitable for development. (p.169)

Article IX Section 9.6 Density Bonuses
The DRB may, at the request of the applicant, grant one or more density bonuses according to the following schedule for clustered development that meets stated objectives under Section 9.1 and below, if the applicant clearly demonstrates that the developable portion of the parcel(s) and supporting roads, infrastructure, facilities and services can accommodate higher densities of development. Density bonuses, as applied in combination, shall not increase the overall density of development by more than 100%, based on the number of dwelling units for residential development ("yield" density calculated under section 9.5.C), or the maximum building coverage for nonresidential development. (p.170)

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