Impact Analysis: What the Expansion Actually Covers
The Parker bill expands the TOC radius from 500 ft to 1,320 ft around 13 MFL stations. But only commercially-zoned parcels receive new development capacity. Here's the real scope.
The Expansion: 500 ft vs. 1,320 ft
How many more commercially-zoned parcels does the radius expansion actually capture?
The existing 500 ft overlay covers 1,686 eligible parcels. The Parker expansion to 1,320 ft adds 7,522 more — a 5.5x increase.
Most Parcels in the Radius Are Unaffected
Of the 18,652 parcels within the expanded radius, most are single-family and receive zero changes.
Only 9,208 of 18,652 parcels (49.4%) in the expanded radius have zoning eligible for any TOC bonus. The remaining 9,444 are single-family residential (RSA, RSD), townhouse (RTA), and other categories explicitly excluded from additional density.
Eligible by Zoning District
Housing Yield: Three Ways to Count
Using BPN's zoning rules engine, we estimate TOC housing capacity at three levels of realism.
Theoretical counts every eligible parcel at max zoned capacity with TOC bonuses. Near-term opportunities narrows to realistic redevelopment sites — vacant lots, surface parking, deteriorated buildings, and properties using less than half of their zoned capacity. Realistic applies construction cost-cliff constraints.
What is the cost cliff? Building codes require steel/concrete construction above 7 stories, which costs 32% more per square foot than wood-frame ($216 vs $171/sqft in Philadelphia). A developer won’t build 8-9 stories unless the zoning allows enough floor area to justify that higher cost — typically 800%+ FAR. The 30% bonus is calculated on the base FAR (500% × 1.3 = 650%), adding about two floors and bringing CMX-3 to 9 stories — the range the study finds least cost-efficient, without enough added capacity to offset Type I costs. See Room to Grow for the full massing analysis.
The headline figure includes the MIN overlay’s effect (~2,566 additional units blocked in Districts 3 & 7), detailed below.
Near-Term Opportunity Sites by Category
| Zone | Parcels | Opportunity Sites | If All Built to Max | Realistic (before MIN) | Realistic (with MIN) |
|---|---|---|---|---|---|
| RM-1 | 7,449 | 960 | +16,407 | +3,929 | +3,669 |
| CMX-3 | 235 | 178 | +6,690 | +3,486 | +2,158 |
| CMX-2 | 1,066 | 239 | +5,274 | +2,250 | +1,553 |
| CMX-2.5 | 346 | 68 | +1,602 | +612 | +364 |
| RMX-3 | 35 | 24 | +304 | +156 | +156 |
| CMX-4 | 20 | 13 | +228 | +33 | +0 |
| CMX-1 | 57 | 10 | +36 | +4 | +4 |
Yield by Station
| District | Station | Parcels | Realistic (before MIN) | Lost to MIN | Realistic (with MIN) |
|---|---|---|---|---|---|
| D1 (Squilla) | Spring Garden | 150 | +2,479 | — | +2,479 |
| D3 (Gauthier) | 46th Street | 88 | +1,488 | -1,133 | +355 |
| D3 (Gauthier) * | 60th Street | 72 | +907 | — | +907 |
| D3 (Gauthier) * | 63rd Street | 233 | +845 | — | +845 |
| D3 (Gauthier) | 52nd Street | 89 | +662 | -289 | +373 |
| D4 (Jones) * | 56th Street | 74 | +337 | -26 | +311 |
| D6 (Driscoll) | Frankford TC | 66 | +1,148 | -827 | +321 |
| D7 (Lozada) | Berks | 203 | +939 | -18 | +921 |
| D7 (Lozada) * | Huntingdon | 106 | +739 | -195 | +544 |
| D7 (Lozada) * | Somerset | 142 | +290 | -78 | +212 |
| D7 (Lozada) | Allegheny | 134 | +252 | — | +252 |
| D7 (Lozada) * | Tioga | 118 | +237 | — | +237 |
| D7 (Lozada) * | Erie-Torresdale | 17 | +147 | — | +147 |
CMX-1 Reform: Unlocking Philadelphia's Neighborhood Commercial Corridors
The CMX-1 reform bill (260336) would replace contextual standards with uniform CMX-2 standards for all 5,255 CMX-1 parcels — a potential 9,638 additional housing units.
Four Policy Scenarios for CMX-1 Parcels
Confidence Levels: Not All CMX-1 Parcels Are Equal
CMX-1 is a contextual district — its dimensional standards (height, density, FAR) are inherited from the most restrictive adjacent non-CMX-1 district. Our PostGIS adjacency analysis classified 3,712 parcels (71%) as high-confidence, meaning they abut a clear non-CMX-1 neighbor. The remaining 1,543 parcels (29%) sit on all-CMX-1 blocks with no non-CMX-1 abutting neighbor — a “zoning purgatory” where the current code creates a circular reference. Under the reform bill, these low-confidence parcels see the largest gains because they go from effectively frozen to full CMX-2 capacity.
CMX-1 Housing Capacity by Policy Scenario (All Parcels)
High-Confidence Parcels (3,712)
Low-Confidence Parcels (1,543)
Low-confidence parcels are on all-CMX-1 blocks — circular reference under current law. Status quo TOC has no effect because contextual standards cannot be resolved.
Reform Losers: 392 Parcels Would Lose Capacity
Not every CMX-1 parcel benefits from uniform CMX-2 standards. 392 parcels currently abut higher-density districts (CMX-2.5, RM-2, etc.) and inherit standards that exceed CMX-2. Under the reform bill, these parcels would be downzoned to CMX-2 capacity, losing an estimated 1,368 units of theoretical capacity. This trade-off is worth noting — though the 9,638-unit net gain dwarfs the loss, affected property owners may object.
CMX-1 Reform Impact by Council District
| District | Status Quo | Both Bills | Net Gain |
|---|---|---|---|
| CD10 | 726 | 3,563 | +2,837 |
| CD9 | 465 | 1,268 | +803 |
| CD6 | 365 | 766 | +401 |
| CD1 | 612 | 981 | +369 |
| CD7 | 621 | 988 | +367 |
| CD8 | 597 | 924 | +327 |
| CD4 | 300 | 573 | +273 |
| CD2 | 1,121 | 1,239 | +118 |
| CD5 | 851 | 960 | +109 |
| CD3 | 179 | 194 | +15 |
The MIN Overlay: Housing Suppression in Districts 3 & 7
The Mixed-Income Neighborhoods overlay imposes an unfunded 20% affordable housing mandate on 10+ unit projects. Our parcel-enriched reanalysis shows it has devastated housing production.
MIN is estimated to deter ~2,566 units that TOC would otherwise unlock
In Council Districts 3 and 7, the MIN overlay’s unfunded affordability mandate has coincided with an 86% collapse in large-project delivery. MIN blocks the 30% FAR bonus entirely for CMX-3/4/5 parcels and deters large projects in density-bonus zones. Based on observed permit trends, MIN is likely to reduce TOC housing capacity by an estimated 8.6% of the Mayor’s 30,000-home goal.
TOC Yield: With vs. Without MIN Deterrent (CD3 + CD7)
| CD3 (Gauthier) | CD7 (Lozada) | Combined | |
|---|---|---|---|
| TOC bonus units (no MIN) | 4,239 | 3,752 | 7,991 |
| With MIN deterrent | 2,791 | 2,634 | 5,425 |
| Bonus units lost | 1,448 | 1,118 | 2,566 |
| Near-term sites in MIN | 206 | 136 | 342 |
Why Is District 3's Impact So Much Larger?
District 3’s four western MFL stations (46th through 56th Street) are almost entirely inside the MIN overlay — 46th Street is 100% covered, 52nd Street 97%. These stations also have a heavy concentration of CMX-2 and CMX-2.5 parcels with larger lot sizes that cross the 10-unit threshold where MIN’s inclusionary requirement kicks in. District 7’s MIN coverage is concentrated at Frankford TC (86%) and partially at Somerset (41%) and Huntingdon (66%), but many D7 parcels are small RM-1 lots that stay under 10 units and are not legally subject to the mandate.
What Would Work Better?
The MIN overlay was intended to create affordable housing, but its unfunded 20% mandate at 40% AMI has coincided with a sharp decline in development activity. A funded inclusionary zoning program — like Portland’s, which pairs mandates with tax exemptions — would likely produce far more affordable housing without discouraging market-rate construction. See our full MIN impact analysis for the complete evidence, including difference-in-differences methodology and peer city comparisons.
The Cost Cliff: 1,532 Units Unlikely to Be Built
The 30% FAR bonus for CMX-3 brings buildings to 9 stories, where the cost study finds the weakest returns.
CMX-3 and the Cost Cliff
The 30% FAR bonus is calculated on the base FAR (500% x 1.3 = 650%), adding about two floors and bringing CMX-3 to 9 stories. The cost study finds 8-9 stories is where returns are weakest: it requires Type I (steel/concrete) and its ~32% higher cost without enough added floor area to offset it, so the economics favor stopping at 7.
On affected CMX-3 parcels, the TOC bonus creates capacity for additional floors that is difficult to build economically, because Type I construction costs outpace the added floor area.
What Would Work Better?
Two approaches could unlock the lost units: (1) Increase the FAR bonus to 800%+ so developers can justify 12-story steel/concrete construction and clear the cost cliff entirely, or (2) redesign the bonus to maximize density within 7-story wood-frame construction rather than pushing to 9 stories — more units per floor instead of more floors.
Combined Overlay Impact
Two overlays actually restrict TOC bonus capacity inside the transit radius: /MIN covers 1,759 of the 9,208 eligible parcels and /VDO covers 606. Other overlays (e.g. /SEV) touch more parcels but impose no TOC dimensional or bonus limits.
| Overlay | Effect | Units Lost |
|---|---|---|
| /MIN | Blocks FAR bonus in CMX-3/4/5; deters 10+ unit projects via unfunded affordability mandate | 2,566 |
MIN is the dominant overlay barrier: 2,566 TOC bonus units lost on opportunity sites
MIN costs 2,566 TOC bonus units on near-term opportunity sites — 24.5% of the total near-term yield — split between a legal FAR-bonus block (1,361 units) and a behavioral deterrent on 10+ unit projects (1,205 units). /VDO also caps CMX-2 density below what the TOC bonus would allow, but that constraint is already reflected in the realistic yield above rather than an additional loss on top.
Methodology & Data Sources
Parcel data: Philadelphia Office of Property Assessment (OPA) via CARTO. 551,509 eligible parcels with TOC-eligible zoning classifications citywide.
Zoning capacity: Computed using BPN’s zoning rules engine, which implements Philadelphia Zoning Code (Title 14) dimensional standards tables (14-701-1 through 14-701-4). GFA-based unit estimates for density-bonus zones (coverage × stories × lot area) and FAR-based for commercial zones. Average unit size: 750 sqft.
Construction cost thresholds: Eriksen & Orlando, “Returns to Scale in Residential Construction,” Real Estate Economics (2022). Philadelphia-specific cost data: $166/sqft (wood frame, 1-3 stories), $171/sqft (wood frame, 4-7 stories), $216/sqft (steel/concrete, 8+ stories).
Near-term opportunity sites: Parcels classified as vacant land, surface parking, deteriorated condition, $0 building value (non-vacant), severely underutilized (≤33% of capacity), moderately underutilized (34-50%), auto-oriented uses, single-story commercial on high-capacity zoning, and high land-value-ratio properties (>80% of assessed value is land).
Overlay restrictions: Spatial join with Zoning Overlays shapefile from OpenDataPhilly. /MIN has two distinct effects. First, a legal block of the FAR bonus in CMX-3/4/5/RMX-3 per §14-513(5)(a)(.2) (1,361 units) — a statutory exclusion, not an estimate. Second, a behavioral deterrent on 10+ unit projects in density-bonus zones (1,205 units), estimated from a 0.54 within-district difference-in-differences rate (new-construction permits ≥10 units, CD3 + CD7, pre- vs post-MIN; inside 27.7→8.7/yr against a market-adjusted 18.7/yr counterfactual). /FNE caps height at 35ft. /VDO caps CMX-2 density (already reflected in the realistic yield). /WST blocks bonuses in CMX-4.
Sensitivity: The 0.54 rate is new-construction-specific because TOC density bonuses drive new development, not the additions/alterations that rose inside MIN as a conversion workaround. A broader all-permit-types rate (0.36–0.44) would lower the behavioral deterrent to roughly 800–960 units, leaving a realistic yield of about 7,990–8,150 with MIN. The legal FAR block (1,361 units) is unaffected by the rate.
7,904 New Homes Are Possible — With Stronger TOC Zoning
Strengthening the FAR bonus, adding BSL stations, and reforming the MIN overlay would push that number even higher. Council should act.
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