Sources

Every number the Prosperia simulator takes from its data files, with its value, source and links. 72 are marked PLACEHOLDER or VERIFY: not yet citable. Back to the simulator.

Observed baselines

data/baselines.json

Number	Value	Source	Links
`medianGrossRent`	1,613 (2024)	Median gross rent, ACS 2020-2024 5-year estimates (table B25064), U.S. Census Bureau: Chapel Hill town, North Carolina. The newest town-level survey: Chapel Hill (about 62,000 people) is too small for 1-year ACS estimates, and the 2021-2025 5-year release comes in December 2026. Earlier vintage: $1,483 (2019-2023).	censusreporter.org
`meanCommuteMin`	19.5 (2024)	Mean travel time to work = aggregate minutes (B08013) / workers who did not work from home (B08303), ACS 2020-2024 5-year, Chapel Hill town: 19.52 minutes.	censusreporter.org
`medianHomeValue`	613,700 (2024)	Median value of owner-occupied housing units, ACS 2020-2024 5-year estimates (table B25077), Chapel Hill town, North Carolina.	censusreporter.org
`population`	63,565 (2025)	U.S. Census Bureau, Vintage 2025 population estimates for cities and towns (SUB-EST2025), Chapel Hill town, NC, July 1, 2025 (Orange County part 60,643 + Durham County part 2,922). 2020 Census count: 61,960. ACS 2020-2024 (household population 50,403 + group quarters 11,204): 61,607.	www2.census.gov
`housingUnits`	23,581 (2024)	Housing units, ACS 2020-2024 5-year estimates (table B25001), Chapel Hill town, NC: 21,189 occupied and 2,392 vacant (B25002). Same survey as the households, renters and incomes in shared/luti/data.js, so vacancy is measured consistently. The Census Bureau publishes no newer count of homes for towns (its housing-unit estimates stop at counties). 2020 Census: 23,713. Building permits since (Census BPS): 151 in 2020, 450 in 2021, 200 in 2022, 739 in 2023, 159 in 2024, 155 in 2025 and 109 in January-August 2026. Research note	censusreporter.org
`treeCoverPct`	46.9 (2021)	USFS / MRLC NLCD Tree Canopy Cover, CONUS v2021-4, 30 m. Our calculation: mean canopy of the pixels inside the map area (bbox in meridian-city/fetch_osm.py). The Town publishes no official canopy figure. 30 m data reads low in urban areas; EPA EnviroAtlas 1 m land cover (2010) gives 50.3% over the same area. Research note	mrlc.gov
`mapAreaAcres`	1,932	Derived: the 2.8 km square the map covers (bbox in meridian-city/fetch_osm.py)

Model assumptions

data/assumptions.json

Number	Value	Source	Links
`rentSupplyElasticity`	-0.1	Li (2022), "Do New Housing Units in Your Backyard Raise Your Rents?", Journal of Economic Geography: a 10% increase in housing stock within 500 ft lowers rents 1%. Alternate: -0.19. Mense (2025), Journal of Political Economy Macroeconomics: 1% new housing supply lowers average rent 0.19%.
`propertyTaxRate`	0.005	Town of Chapel Hill FY2026-27 adopted budget: 50.0 cents per $100 of assessed value (General Fund 38.1, Debt Service 6.6, Transit 5.3), unchanged from FY2025-26.	chapelhillnc.gov
`canopyMinPct`	low_res 0.4 · mid_res 0.3 · mixed_use 0.2 · parking 0.2 · transit_station 0.2	Chapel Hill Land Use Management Ordinance (LUMO) Section 5.7: tree canopy minimums of 20-40%. Which value in that range applies to each zone state is our mapping, not the ordinance's. Forest counts as full canopy.
`unitsPerAcre`	forest 0 · low_res 4 · mid_res 15 · mixed_use 70 · parking 0 · transit_station 0	Town of Chapel Hill Future Land Use Map, "Charting Our Future" (Dec 2020): Low Residential 1-4 units/acre, High Residential 8-15+,; last codified LUMO Table 3.8-1 density caps (R-2 4.0, R-5 and R-6 15.0),; approved mixed-use projects: Fordham Blvd Apartments (Chapelboro, 2017-05-09), Aura Blue Hill (News & Observer, 2021-10-28), 101 E. Rosemary St (Town staff report, 2023) Which district stands for which zone state is our mapping. mixed_use 70 is the low end of three approved Chapel Hill projects (about 70, 99 and 214 units/acre, our calculation); a suburban-village style (MU-V arterial cap) would be about 20. Chapel Hill removed its residential density caps in 2023 (Ord. 2023-06-21/O-6). Research note	online.flippingbook.com · api.municode.com · chapelboro.com · yahoo.com · chapelhill.legistar1.com
`treesPerAcre`	33	USDA Forest Service FIA, EVALIDator (FIADB-API), NC 2024 evaluation, Piedmont unit 3703: 30.5 live trees per acre at 13 in. DBH or more. Counts large trees only (about 13 in. DBH and up), which matches the renderer's 11 m tree spacing. At 5 in. and up the Piedmont average is 177 per acre (our calculation). Not used by the metrics yet. Research note	apps.fs.usda.gov
`commuteDistancePenalty`	0.6 minutes	ACS 2020-2024 5-year: mean travel time = B08013 (aggregate minutes) / B08303 (workers who did not work from home), by census tract. and Our calculation: map_edge zones, assigned to tracts by centroid and weighted by acres, average 20.1 min vs 19.5 town-wide. That is inside the tracts' margins of error, so statistically indistinguishable from 0. Used by the aggregate sim; the page's commute comes from the household model. Research note	data.census.gov · data.census.gov
`agentScale`	70.63	Derived: 21,189 households (occupied homes, ACS 2020-2024 5-year, B25002) / 300 simulated households. Each simulated household stands for this many real ones, so the households and priced-out counts are in real households. It was homes per simulated household (79), which counted vacant homes as households.
`agentHouseholds`	downtown 105 · campus 98 · edge 97 · corridor 0	PLACEHOLDER needs citation Simulated households per zone at year 0. From the household-model prototype.
`agentUnits`	downtown 108 · campus 101 · edge 100 · corridor 0	PLACEHOLDER needs citation Simulated homes per zone at year 0. Homes the zone rules build are added by parcel: corridor parcels to corridor, other map_edge parcels to edge, the rest to downtown. CH-LUTI's other new homes are added by its zone: downtown and north to downtown, campus to campus, east and south (which commute over 15-501) to edge. From the household-model prototype.
`agentBurdenLine`	0.3	U.S. Census Bureau ACS 2020-2024 5-year, B25070 "Gross Rent as a Percentage of Household Income", Chapel Hill town, which reports renters paying 30% or more; HUD counts households paying more than 30% of income for housing as cost-burdened. Rent share of income above which burden that builds up after arrival counts toward leaving (see agentLeaveRate). The 30% line is the standard; using it in a leaving rule is our modelling choice.	data.census.gov
`agentLeaveRate`	0.003 per point of burden, per year	PLACEHOLDER needs citation Each year a renter leaves with chance 1 - e^(-rate x points), counting only burden above 30% (agentBurdenLine) that has built up since they arrived: points above the higher of 30% and their burden on arrival. Rents follow CH-LUTI and incomes grow as CH-LUTI's do, so this is rent rising faster than income. Priced out counts year-0 households only; about 1 in 100 renters per 1% rent rise above no policy (tests/agents.test.js).
`agentRenterShare`	downtown 0.6 · campus 0.8 · edge 0.35 · corridor 0.6	PLACEHOLDER needs citation From the household-model prototype. Corridor (new apartments near 15-501) takes downtown's value. At year 0 these give 58.6% renters town-wide against 52.6% in the ACS (2020-2024, B25003: 11,141 of 21,189 households). Kept for now because the showcase residents (data/residents.json) are seed-7 households picked by tenure; scaling these by 0.9 matches the ACS but redraws them.
`agentStudentShare`	0.4	Our calculation from ACS 2020-2024 5-year, Chapel Hill town: 21,533 enrolled in college or graduate school (B14001) less 11,204 in group quarters, mostly residence halls (B26001), leaves about 10,300 students in households; at 2.13 people per renter household (B25010) that is about 4,800 households, or 43% of the 11,141 renter households (B25003). Share of renters who are students. Rounded down to the prototype's 0.4, since some students live with non-students.
`agentIncomeMedian`	student 43200 · renter 69100 · owner 180900	Owners: ACS 2020-2024 5-year, B25119 Median household income by tenure, Chapel Hill town: $180,885. Students and other renters: the prototype's values (40,000 and 64,000) scaled by 1.08 so that, at the ACS 2020-2024 median gross rent of $1,613 (B25064), 60.8% of renters pay 30% or more of income in rent, as in B25070. Median household income by type (log-normal). Over 60 runs, 60.5% of year-0 renters pay 30% or more of income in rent (ACS: 60.8%) and the median pays 34.3% (ACS B25071: 36.0%). The model's renters' median income is about $55,700 against $50,439 in the ACS: the model draws rents independently of incomes, so it can't match rent burden and income at once, and rent burden is what moves households. A wider income spread fits all three better but pushed a showcase resident (Quinn) into debt with no policy.	censusreporter.org
`agentIncomeSpread`	student 0.35 · renter 0.45 · owner 0.4	PLACEHOLDER needs citation Log-normal spread of income by type. From the household-model prototype.
`agentRemoteShare`	0.28	ACS 2020-2024 5-year, B08301 "Means of Transportation to Work", Chapel Hill town: 8,174 of 29,039 workers worked from home. A 2020-24 average that includes the 2021 peak (2019-2023: 0.271). Alternate: 0.235. Our calculation: Orange County's 2024 1-year to 2020-24 5-year ratio (22.4% / 26.8%) applied to Chapel Hill.	data.census.gov · data.census.gov
`agentDurhamShare`	0.2	U.S. Census Bureau LEHD Origin-Destination Employment Statistics (LODES 8), NC 2023, primary jobs (JT01): 4,225 of 20,644 Chapel Hill residents' primary jobs are in Durham city. Our calculation, joined to the LODES block crosswalk. Durham County would be 0.25.	lehd.ces.census.gov
`agentCampusWorkShare`	0.5	PLACEHOLDER needs citation Of the rest, non-students working on campus (others work downtown). From the household-model prototype.
`agentZoneRent`	downtown 1.1 · campus 1 · edge 0.92 · corridor 1.1	PLACEHOLDER needs citation Rent level by zone, before calibration to the ACS median gross rent. From the household-model prototype. Corridor takes downtown's value.
`agentRentSpread`	min 0.82 · range 0.4	PLACEHOLDER needs citation Each home's rent varies from min to min + range of its zone level. From the household-model prototype.
`agentBaseCommuteMin`	downtown 7 · campus 5 · edge 6 · corridor 7	PLACEHOLDER needs citation Local commute by zone, before calibration to the ACS mean commute. Edge households also drive 15-501; corridor households don't (no distance penalty), so corridor takes downtown's value. From the household-model prototype.
`agentDurhamExtraMin`	9	PLACEHOLDER needs citation From the household-model prototype.
`roadT0Min`	14 minutes	PLACEHOLDER needs citation Free-flow 15-501 travel time. From the household-model prototype.
`roadCapacity`	2,000 vehicles/hour per direction	NCDOT "Volume Over Capacity" layer (capacity lookup by Three Oaks Engineering): US-15 route 20000015068, urban Piedmont, 2 lanes per direction with median, LOS E 37,000 vehicles/day two-way. Our calculation: converted with NCDOT's standard K = 0.09 and D = 0.6. The 15-501 segment on the map is Fordham Blvd, a signalized boulevard; NCDOT's 2021 capacity table gives about 1,955 for that facility type.	services.arcgis.com
`roadPeakVolume`	1,960 vehicles/hour per direction	NCDOT 2025 AADT, station 0680000193 "US 15 WEST OF Morgan Creek Rd": 41,500 vehicles/day, segment K = 0.08 and D = 0.591. Our calculation: peak-hour, peak-direction demand. 15-501 starts at 98% of capacity, and its load then follows CH-LUTI's car traffic.	services.arcgis.com
`roadBpr`	alpha 0.15 · beta 4	PLACEHOLDER needs citation BPR delay curve: time = t0 x (1 + alpha x (volume/capacity)^beta). From the household-model prototype.
`lutiRegionalGrowth`	lo 0.0035 · mid 0.0073 · hi 0.015 /yr	PLACEHOLDER lo and hi need citation. mid: U.S. Census Bureau decennial census households (occupied housing units), Chapel Hill town: 20,564 in 2010 (SF1 H3) and 22,118 in 2020 (P.L. 94-171 H1) Growth of households looking to live in the area (location choice). mid is our calculation: compound growth 2010-2020, a historical rate, not a forecast. lo and hi are a placeholder range; the CH-LUTI model had lo 0.008, mid 0.015, hi 0.022. With homes from permit trends (lutiStartShare, Census Building Permits Survey 2015-2025), this sets the no-policy growth of homes and households for every model.	data.census.gov · data.census.gov
`lutiAccessElasticity`	lo 0.3 · mid 0.6 · hi 1	PLACEHOLDER needs citation Pull of better access to jobs in the location-choice logit. The model's note: hedonic studies put housing-price elasticities to job access around 0.1-0.3, scaled by the rent elasticity; no study cited. From the CH-LUTI model.
`lutiVibrancyElasticity`	lo 0.1 · mid 0.3 · hi 0.6	PLACEHOLDER needs citation Pull of busy storefronts nearby in the location-choice logit. The model's note: amenity evidence (e.g. Glaeser, Kolko & Saiz 2001, "Consumer City") is qualitative. From the CH-LUTI model.
`lutiJobsHousingElasticity`	lo 0.2 · mid 0.35 · hi 0.5	PLACEHOLDER needs citation Housing demand per extra job in Town. The model's reasoning: over half of Town jobs are held by in-commuters (LODES 54k jobs vs 30k resident workers), so demand responds well below 1:1. From the CH-LUTI model.
`lutiBizDemandResponse`	lo 0.5 · mid 1 · hi 1.5	PLACEHOLDER needs citation How fast storefront openings and closures react to local spending (stock-and-flow adjustment speed). From the CH-LUTI model.
`lutiVacancyTaxLeaseUp`	lo 0.02 · mid 0.06 · hi 0.12 /yr per 1% tax	PLACEHOLDER needs citation Extra share of vacant storefronts leased per year, per 1% vacancy tax. San Francisco (2022) and Washington DC tax vacant storefronts; neither has a causal evaluation yet. From the CH-LUTI model.
`lutiMarginalServiceCost`	lo 0.4 · mid 0.6 · hi 0.9 x average	PLACEHOLDER needs citation Cost of serving a new resident, relative to the average (FY2025-26 general fund / population is about $1,540 per resident). From the CH-LUTI model.
`lutiHouseholdAdjust`	0.25	PLACEHOLDER needs citation Share of the gap between desired and actual households closed each quarter (leases turn over yearly). From the CH-LUTI model.
`lutiMinVacancy`	0.015	PLACEHOLDER needs citation Lowest home vacancy the market reaches. From the CH-LUTI model.
`lutiIncomeGrowth`	0.0275 /yr	U.S. Census Bureau QuickFacts, Chapel Hill town, North Carolina (ACS 5-year estimates): median gross rent $1,172 (2014-2018) and $1,483 (2019-2023); median household income $68,640 (2014-2018) and $85,825 (2019-2023). Nominal household income growth, for rent burden in CH-LUTI and the household model. Our calculation: over those five years rent grew 4.82%/yr and income 4.57%/yr, so incomes trailed rents by 0.25 points a year. CH-LUTI's rent path rises with rentDrift (3%/yr at its central value, Zillow ZORI), so incomes grow 3% - 0.25 points = 2.75%/yr.	census.gov
`lutiCpi`	0.023 /yr	Federal Reserve Bank of Philadelphia, Survey of Professional Forecasters, Third Quarter 2026: headline CPI inflation over the next 10 years (2026-2035), 2.30% a year. Inflation applied to sales tax, service costs and programme costs, and the default for the inflation what-if (shared/luti/drivers.js). Recent: CPI-U +3.4% over the 12 months to August 2026 (BLS, released September 11, 2026).	philadelphiafed.org
`lutiRegionShare`	0.05	PLACEHOLDER needs citation Chapel Hill's share of the regional pool of movers; sets how readily households choose other places in the location-choice logit. From the CH-LUTI model.
`lutiUnitSizeSf`	950 sq ft	PLACEHOLDER needs citation Size of a typical new apartment in the development pro forma. From the CH-LUTI model.
`lutiSoftCost`	0.25	PLACEHOLDER needs citation Soft costs (design, fees, financing) as a share of hard cost. From the CH-LUTI model.
`lutiOpex`	0.35	PLACEHOLDER needs citation Operating expenses as a share of rent. From the CH-LUTI model.
`lutiStabilizedVacancy`	0.05	PLACEHOLDER needs citation Vacancy a developer assumes for a finished building. From the CH-LUTI model.
`lutiHurdle`	0.15	PLACEHOLDER needs citation Developer profit on cost needed to build. From the CH-LUTI model.
`lutiCalibrationGap`	0.03	PLACEHOLDER needs citation In the base year the marginal site is this far short of the hurdle (a market near equilibrium). From the CH-LUTI model.
`lutiBuildQuarters`	8 quarters	PLACEHOLDER needs citation Time from construction start to completion. From the CH-LUTI model.
`lutiCostDrift`	0.03 /yr	PLACEHOLDER needs citation Construction cost inflation. From the CH-LUTI model.
`lutiSurfaceParkingCost`	6,000 $/space	PLACEHOLDER needs citation Cost of a surface parking space. From the CH-LUTI model.
`lutiLandPerUnit`	downtown 55000 · campus 50000 · north 40000 · east 45000 · south 35000 $/home	PLACEHOLDER needs citation Land cost per new home by zone. The model's note: derived from Orange County land values / typical density; no source cited. From the CH-LUTI model.
`lutiStructuredParking`	downtown 1 · campus 1 · north 0 · east 1 · south 0	PLACEHOLDER needs citation 1 where new homes park in a garage, 0 where they use a surface lot. From the CH-LUTI model.
`lutiParkingMinimum`	downtown 0 · campus 0 · north 0 · east 0 · south 0 spaces/home	Town of Chapel Hill: on January 21, 2026 the Town Council adopted Land Use Management Ordinance amendments that eliminate mandatory parking minimums across town. Parking required per new home today. With none required, builders build what the market asks for (marketParkingRatio in shared/luti/params.js); the housing.parkingMinimum lever can bring a requirement back.	engage.chapelhillnc.gov
`lutiStartShare`	downtown 0.25 · campus 0.05 · north 0.25 · east 0.35 · south 0.1	PLACEHOLDER needs citation Share of the Town's construction starts (about 334 homes a year, Census Building Permits Survey 2015-2025) that land in each zone. From the CH-LUTI model.
`lutiProjectSize`	downtown 120 · campus 80 · north 150 · east 180 · south 40 homes	PLACEHOLDER needs citation Homes per building when construction starts are turned into building events for a renderer. From the CH-LUTI model.
`lutiProjectFloors`	downtown 6 · campus 5 · north 5 · east 6 · south 3 floors	PLACEHOLDER needs citation Floors per building event at today's allowed floor area. From the CH-LUTI model.
`lutiStorefrontVacancyElsewhere`	0.1	PLACEHOLDER needs citation Storefront vacancy outside downtown at the start (downtown's 24% is the Downtown Partnership survey in shared/luti/data.js). From the CH-LUTI model.
`lutiRetailSpacesPerUnit`	0.025 storefronts/home	PLACEHOLDER needs citation Ground-floor storefronts that come with new mixed-use apartments downtown and in the East zone (1 per 40 homes). From the CH-LUTI model.
`lutiSpendingFromJobs`	0.45	PLACEHOLDER needs citation Share of storefront spending that comes from people who work in Town. From the CH-LUTI model.
`lutiLocalSpendShare`	0.5	PLACEHOLDER needs citation Share of a zone's storefront demand that comes from its own residents; the rest follows Town-wide spending. From the CH-LUTI model.
`lutiGrantSize`	10,000 $	PLACEHOLDER needs citation Size of one small-business support grant. From the CH-LUTI model.
`lutiStartupGrantSize`	25,000 $	PLACEHOLDER needs citation Size of one start-up grant. From the CH-LUTI model.
`lutiHiringJobAttrition`	0.2 /yr	PLACEHOLDER needs citation Share of the jobs a hiring subsidy created that end each year. From the CH-LUTI model.
`lutiAtRiskMultiple`	2	PLACEHOLDER needs citation Grant recipients are businesses closing at this multiple of the usual rate. From the CH-LUTI model.
`lutiStorefrontValue`	600,000 $	PLACEHOLDER needs citation Assessed value of a typical storefront bay, for the vacancy tax. From the CH-LUTI model.
`lutiLongVacantShare`	0.5	PLACEHOLDER needs citation Share of vacant storefronts empty long enough to owe the vacancy tax. From the CH-LUTI model.
`lutiInCommuterTransitShare`	0.15	PLACEHOLDER needs citation Share of in-commuters who ride transit today. From the CH-LUTI model.
`lutiInCommuterTransitMax`	0.6	PLACEHOLDER needs citation Upper limit on that share as bus service grows. From the CH-LUTI model.
`lutiRidershipFromResidents`	0.5	PLACEHOLDER needs citation Share of bus ridership that follows resident population; the rest follows jobs in Town. From the CH-LUTI model.
`lutiPeakVC`	0.9	PLACEHOLDER needs citation Peak volume / capacity on the main corridors, for car speeds (with roadBpr). From the CH-LUTI model.
`lutiSpeedKmh`	car 30 · bus 18 · bike 14 · walk 4.8 · regionCar 55 · regionBus 35 km/h	PLACEHOLDER needs citation Speeds in Town, and to Durham and RTP for out-commuters. From the CH-LUTI model.
`lutiIntraZoneKm`	downtown 1.4 · campus 1.8 · north 2.5 · east 2.5 · south 2.2 km	PLACEHOLDER needs citation Typical commute length within a zone. From the CH-LUTI model.
`lutiCircuity`	1.3	PLACEHOLDER needs citation Street-network distance / straight-line distance between zones. From the CH-LUTI model.
`lutiTerminalMin`	parkingScarce 9 · other 3 minutes	PLACEHOLDER needs citation Park-and-walk time at the end of a car commute: downtown and campus (UNC permits, decks) vs. elsewhere and out of Town. From the CH-LUTI model.
`lutiBusAccessMin`	5 minutes	PLACEHOLDER needs citation Walk to or from a bus stop. From the CH-LUTI model.
`lutiActiveModeWeight`	1.5	PLACEHOLDER needs citation Bike and walk minutes count this many times an in-vehicle minute in mode choice. From the CH-LUTI model.
`lutiOvtWeight`	2	PLACEHOLDER needs citation Waiting and walking to the bus, and parking, count this many times an in-vehicle minute. From the CH-LUTI model.
`lutiBikeStressMin`	10 minutes	PLACEHOLDER needs citation Cycling stress penalty without a protected network. From the CH-LUTI model.
`lutiBikeNetwork`	referenceKm 12 · maxEffect 1.5	PLACEHOLDER needs citation bikeInfraEffect is the stress removed by referenceKm of protected lanes; a longer network scales it, up to maxEffect times. From the CH-LUTI model.
`lutiBikeLaneCost`	capitalPerKm 800000 · debtServicePerYear 0.0736 · upkeepPerKm 8000 $	PLACEHOLDER needs citation Protected bike lane cost: capital per km, yearly debt service per dollar of capital, yearly upkeep per km. From the CH-LUTI model.
`lutiGravityDecay`	0.3 /km	PLACEHOLDER needs citation Distance decay in choosing a work zone. From the CH-LUTI model.
`lutiAccessDecay`	0.12 /min	PLACEHOLDER needs citation Time decay in the job-accessibility index. From the CH-LUTI model.
`lutiHeadwayMin`	downtown 15 · campus 10 · north 18 · east 23 · south 13 minutes	Our calculation from Chapel Hill Transit's GTFS feed, Fall 2026 Update (valid from October 9, 2026), via the Mobility Database (feed tld-89). Typical peak minutes between buses at a stop in each zone: weekday 7-9 am departures on local routes (express, park-and-ride shuttle and school routes left out), the busier direction at each stop, averaged over the zone's stops as a frequency (harmonic mean). Stops west of the Town line (Carrboro) are left out. Zones are the nearest representative point, as in shared/luti/data.js.	files.mobilitydatabase.org
`lutiRegion`	outShare 0.45 · distanceKm 16 · headway 30	outShare: ACS 2020-2024 5-year, Chapel Hill town: 9,453 workers worked outside the town (B08008) of the 20,865 who did not work from home (29,039 workers less 8,174 at home, B08301), 45.3%.. distanceKm and headway: PLACEHOLDER - need citation. Commutes out of Town (Durham, RTP, Raleigh): share of resident commuters, distance in km, minutes between regional buses. LEHD LODES 2023 puts 72% of residents' primary jobs outside town, but it files many UNC System jobs at a Raleigh headquarters (19% of residents' jobs show in Wake County), so the ACS's answer from residents is used.	censusreporter.org
`lutiTransitTownShare`	0.34	Town of Chapel Hill FY2026-27 adopted budget, Transit Fund revenue projections: the Town's transit property tax ($7,491,000) and vehicle tax ($450,000) are 34% of the three partners' contributions, with UNC ($12,624,606) and Carrboro ($2,673,487). Town's share of the cost of extra Chapel Hill Transit service, assuming added service is shared as today's is.	chapelhillnc.gov
`lutiRevaluationYears`	2029, 2033, 2037, 2041, 2045, 2049, 2053	Orange County, 2025 Property Revaluation: the 2025 revaluation is as of January 1, 2025 and the next is January 1, 2029, on a four-year cycle. Years Orange County revalues property; each resets the base tax rate to revenue-neutral. 2033 onward assume the four-year cycle continues, to the end of a three-decade game.	orangecountync.gov
`lutiResidentialShareOfBase`	0.8	PLACEHOLDER needs citation Residential share of the Town's taxable value. From the CH-LUTI model.
`lutiRenterTaxShare`	0.5	PLACEHOLDER needs citation Share of a property tax change that renters feel, in location choice. From the CH-LUTI model.
`lutiLandCatchUpQuarters`	12 quarters	PLACEHOLDER needs citation Land prices close the gap to an upzoning's value by 1/this each quarter (about three years). From the CH-LUTI model.
`lutiAffordableGap`	0.4	PLACEHOLDER needs citation How far below the new-build market rent a home under an affordable-housing requirement rents, as a share of that rent. Used by the housing.inclusionaryPct lever.
`lutiApprovalCarryPerYear`	0.04 /yr	PLACEHOLDER needs citation Extra cost of a new home per year of longer permit approval, as a share of its cost (land and loans held longer). Used by the housing.approvalMonths lever.
`lutiValueOfTimePerHour`	20 $/hour	PLACEHOLDER needs citation What a commuter would pay to save an hour, to weigh a daily parking charge against travel time. Used by the transport.parkingPriceDelta lever.
`lutiCarCo2GramsPerMile`	400 g CO2/mile	U.S. EPA, Greenhouse Gas Emissions from a Typical Passenger Vehicle: about 400 grams of CO2 per mile (22.2 mpg, 8,887 g CO2 per gallon of gasoline). For the commute CO2 indicator: car-km on commutes (CH-LUTI's travel step) times this. Tailpipe CO2 only, today's fleet; electric cars would lower it.	epa.gov
`lutiTrainingCost`	23,135 $/trainee	Year Up, a sectoral job-training programme evaluated by random assignment: net cost $23,135 per participant (Fein, Dastrup and Burnett 2021), as reported in J-PAL North America, Sectoral Employment Programs evidence review (2022). Cost to the Town of putting one resident through a job-training programme, rising with inflation. Year Up is a full-time, year-long programme with stipends; shorter programmes cost less.	povertyactionlab.org
`lutiTrainingEarningsGain`	0.2	Katz, L., Roth, J., Hendra, R. and Schaberg, K. (2022), Why Do Sectoral Employment Programs Work? Lessons from WorkAdvance, Journal of Labor Economics 40(S1): S249-S291: substantial and persistent earnings gains of 12% to 34% following training. A trained household's income rises by this share from the year after training, while it lives here. Near the middle of the published range.	nber.org
`lutiOtherPropertyTaxCents`	82.84 ¢ per $100	Orange County 2025 tax bill insert: county 68.05¢ and Chapel Hill-Carrboro City Schools district 14.79¢, on top of the Town's own rate. The rest of a Chapel Hill homeowner's property tax bill, which the Town does not set. The combined rate today is 132.84¢ per $100, so the Town's 50.0¢ is 38% of it: a player's rate change moves about a third of the bill.	orangecountync.gov
`lutiWorkdaysPerYear`	250 days	PLACEHOLDER needs citation Days a year a commuter parks, for parking-charge revenue. Used by the transport.parkingPriceDelta lever.
`lutiTownParkingShare`	0.2	PLACEHOLDER needs citation Share of cars bound for the downtown zone (Franklin Street and north campus) that park in Town-run decks, lots and meters; the rest use UNC or private parking the Town doesn't price. Used by the transport.parkingPriceDelta lever.

Resident finances

data/resident-finance.json

Number	Value	Source	Links
`federalStandardDeduction`	single 16100 · joint 32200 $ (2026)	IRS Rev. Proc. 2025-32, inflation adjustments for tax year 2026. Year 0 is 2026. Take-home pay is wages less federal and North Carolina income tax and payroll tax, with the standard deduction and no credits (such as the child tax credit). Students, single renters and "You" file single; families and owners file jointly (data/residents.json). Later years index every dollar threshold with rent inflation (CH-LUTI's rentDrift).	irs.gov
`federalBracketsSingle`	0 0.1 · 12400 0.12 · 50400 0.22 · 105700 0.24 · 201775 0.32 · 256225 0.35 · 640600 0.37 taxable income ($, 2026) where each rate starts	IRS Rev. Proc. 2025-32 (unmarried individuals).	irs.gov
`federalBracketsJoint`	0 0.1 · 24800 0.12 · 100800 0.22 · 211400 0.24 · 403550 0.32 · 512450 0.35 · 768700 0.37 taxable income ($, 2026) where each rate starts	IRS Rev. Proc. 2025-32 (married filing jointly).	irs.gov
`ncIncomeTaxRate`	0.0399	NC Department of Revenue, tax rate schedules: 3.99% for tax years beginning in 2026 and after (S.L. 2023-134).	ncdor.gov
`ncStandardDeduction`	single 12750 · joint 25500 $	NC Department of Revenue, North Carolina standard deduction.	ncdor.gov
`socialSecurityTax`	rate 0.062 · wageBase 184500 employee share; wage base in $ (2026)	IRS Topic 751 (6.2% employee Social Security tax); SSA 2026 taxable maximum $184,500, announced October 2025 (Journal of Accountancy)	irs.gov · journalofaccountancy.com
`medicareTaxRate`	0.0145	IRS Topic 751: 1.45% employee Medicare tax.	irs.gov
`additionalMedicareTax`	rate 0.009 · threshold [object Object] employee rate on wages above the threshold for the filing status ($)	IRS Topic 560, Additional Medicare Tax: 0.9% of wages over $200,000 (single) or $250,000 (married filing jointly). The thresholds are set in law and not indexed.	irs.gov
`ceTotalSpending`	16658 35046 · 42925 50054 · 74474 66900 · 121548 89972 · 264510 150342 average income before taxes of each quintile -> yearly total expenditures, both in 2024 $	BLS Consumer Expenditure Surveys 2024, quintiles of income before taxes (released December 19, 2025), via FRED series CXUTOTALEXPLB0102M-0106M; the keys are each quintile's average income before taxes (CXUINCBEFTXLB0102M-0106M). Other spending (everything but housing and the commute) is what a household of the same income spends in the CE: its after-tax income x (1 - personalSavingRate), times the share of CE spending, less personal insurance and pensions, that is neither shelter nor the commute: (total - insurance and pensions - shelter - commuteShareOfDriving x transportation) / (total - insurance and pensions). The share (about 0.69-0.71) is interpolated on year-0 income between the quintiles (flat beyond the end ones). A household whose rent takes a typical share saves about the national saving rate; one whose rent takes more falls short. Set in year 0, it grows with rent inflation (CH-LUTI's rentDrift).	bls.gov · fred.stlouisfed.org
`ceShelter`	16658 9178 · 42925 11902 · 74474 15257 · 121548 17851 · 264510 27338 average income before taxes of each quintile -> yearly shelter spending, both in 2024 $	BLS Consumer Expenditure Surveys 2024, quintiles of income before taxes (released December 19, 2025), via FRED series CXUSHELTERLB0102M-0106M; the keys are each quintile's average income before taxes (CXUINCBEFTXLB0102M-0106M). Rent, or mortgage interest, property tax, upkeep and insurance: modelled per household instead.	bls.gov · fred.stlouisfed.org
`ceTransport`	16658 5105 · 42925 8430 · 74474 11657 · 121548 15952 · 264510 25378 average income before taxes of each quintile -> yearly transportation spending, both in 2024 $	BLS Consumer Expenditure Surveys 2024, quintiles of income before taxes (released December 19, 2025), via FRED series CXUTRANSLB0102M-0106M; the keys are each quintile's average income before taxes (CXUINCBEFTXLB0102M-0106M). Vehicles, fuel, upkeep, insurance and fares. The commute's part is modelled per household instead.	bls.gov · fred.stlouisfed.org
`ceInsurancePensions`	16658 711 · 42925 2712 · 74474 6248 · 121548 11934 · 264510 27279 average income before taxes of each quintile -> yearly personal insurance and pensions, both in 2024 $	BLS Consumer Expenditure Surveys 2024, quintiles of income before taxes (released December 19, 2025), via FRED series CXUINSPENSNLB0102M-0106M; the keys are each quintile's average income before taxes (CXUINCBEFTXLB0102M-0106M). Mostly Social Security and pension contributions: payroll tax is in take-home pay, and pensions are saving, so this is left out of spending.	bls.gov · fred.stlouisfed.org
`personalSavingRate`	0.054	U.S. Bureau of Economic Analysis, personal saving as a percentage of disposable personal income, 2025 average of the monthly rates (via FRED PSAVERT).	fred.stlouisfed.org
`commuteShareOfDriving`	0.3	VERIFY commuting is reported as about 30% of household vehicle miles in the 2017 and 2022 National Household Travel Survey (summary seen, not yet the primary table). The share of a household's transportation spending that is its commute.	nhts.ornl.gov
`startingSavings`	0 900 · 29932 2600 · 57452 7100 · 94511 15700 · 155925 33700 lower bound of income before taxes (2024 $) -> savings ($, 2022)	Federal Reserve, 2022 Survey of Consumer Finances, Table 6 (family holdings of financial assets): median transaction accounts (checking, savings, money market) of families holding them, by percentile of income: less than 20th 900, 20-39.9 2,600, 40-59.9 7,100, 60-79.9 15,700, 80-89.9 33,700.; quintile lower bounds from BLS Consumer Expenditure Surveys 2024 (29,932 / 57,452 / 94,511 / 155,925). Savings at the start of year 0, by the income quintile of the household's year-0 income, in year-0 dollars. The top quintile takes the 80-89.9 median, not the 90-100 one ($111,100), as no showcase household is near the 90th percentile. No interest. Savings never go below zero: a shortfall after they are gone is bills falling behind.	federalreserve.gov · bls.gov
`carCostPerMile`	0.725 $/mile (2026)	IRS Notice 2026-10 (IR-2025-128): 2026 standard mileage rate for business use, 72.5 cents a mile. A car commute costs commute minutes x CH-LUTI's peak car speed (lutiSpeedKmh.car) x this, so a slower commute costs more. Grows with rent inflation.	irs.gov
`busFare`	town 0 · durham 2.5 $ a trip (2026)	Chapel Hill Transit has been fare-free since 2002 (The Local Reporter); GoTriangle full fare $2.50 durham: a GoTriangle regional bus to Durham. Grows with rent inflation.	thelocalreporter.press · gotriangle.org
`busMonthlyCap`	durham 80 $ a month (2026)	GoTriangle fare capping: $5 a day, $20 a week, $80 a month.	gotriangle.org
`workDaysPerMonth`	21	Derived: 52 weeks x 5 days less 11 federal holidays (5 U.S.C. 6103) is 249 work days a year, about 21 a month. Commuters make two trips each work day; the household model's commute is one way.	law.cornell.edu
`ownerFixedShare`	1	PLACEHOLDER needs citation Owners pay a fixed monthly mortgage and insurance of this x their home's year-0 market rent (the household model's rentBase), plus Town property tax: CH-LUTI's median home value, scaled by that rent against the median, x CH-LUTI's tax rate. County tax is not modelled.