CHCCS Demographics Analysis

ACS = American Community Survey, an ongoing Census Bureau survey. 5-Year means data averaged over 2020-2024 for statistical reliability in small areas like block groups. This is official data collected and published by the U.S. Census Bureau.

A geographic boundary determining which school students are assigned to by default. Important: Zone demographics show who lives in each zone, not who attends each school (families may use school choice, transfers, or magnets).

Areas grouped by which school is closest via that travel mode, using actual road networks (Dijkstra shortest-path algorithm). Walk: 2.5 mph • Bike: 12 mph • Drive: 12-62 mph friction speed + intersection penalties (15 s at signals, 7 s at stops).

Block Groups = Census block groups (~1,500 people), the native ACS geography. Blocks (est.) = Estimated block-level values interpolated from block groups using residential parcel area weighting (dasymetric method).

All non-White-Non-Hispanic residents: Black, Hispanic/Latino, Asian, Multiracial, Native American, Pacific Islander, and other races. Calculated as 100% minus % White Non-Hispanic.

The dots show each racial/ethnic group as separate colors for detailed visualization. % Minority aggregates all non-White-NH groups into one metric for quick zone-to-zone comparison.

The percentage of all residents (not just children) who are aged 5-9. Denominator = total population of all ages in that area.

The percentage of residents with household income below 185% of the federal poverty line. This threshold is the eligibility cutoff for Free/Reduced-price Lunch (FRL) in public schools, making it a useful proxy for school-level economic disadvantage.

Drive zones are based on actual driving distance along roads, not straight-line distance. Two places might look close on a map but be far apart by car if there's no direct road connecting them — they may need to go around a highway, river, or neighborhood without a through-street. So the "nearest school by driving" depends on which roads are available, not just how close things appear.

The travel-time zones are built from a 100-meter grid. Each grid pixel is “snapped” to the nearest road or path in the OpenStreetMap network. Pixels that are more than 200 meters from any road (e.g., in parks, forests, or large undeveloped areas) cannot be assigned a travel time, so they appear as gaps. These holes do not mean nobody lives there — they simply reflect areas where our road-network model has no nearby edge to connect to.

Population dots are placed within Census block boundaries, and some Census blocks extend beyond the CHCCS district perimeter. When a block only partially overlaps the district, its entire population is still represented with dots scattered across the full block geometry. This means a few dots may fall just outside the dashed district boundary line.

Data from the SAPFOTAC 2025 Annual Report (School Adequate Public Facilities Ordinance Technical Advisory Committee), certified June 3, 2025. It lists 21 future residential projects with projected student yields — the estimated number of elementary, middle, and high school students each development will generate, based on the district’s student generation rates.

The bar charts show three breakdowns per zone: total projects, total housing units remaining, and projected elementary students. Click a marker to see per-project detail including all three student-yield figures.

Why does it differ from CH Active Dev? The two datasets come from different sources collected at different times. CH Active Dev is hand-transcribed from the Town of Chapel Hill Active Development page (March 2026) and covers Chapel Hill only; it has unit counts but no student yield estimates. SAPFOTAC is published by the school district’s advisory committee and covers the full CHCCS boundary (Chapel Hill + Carrboro); it adds student yield projections but may reflect an earlier point in time. Some projects appear in both sources; the datasets are not deduplicated.

See the Socioeconomic Methodology page for detailed documentation of data sources, processing steps, and limitations.