Long Island Town Fact Book: sources and method

Each of our 109 town pages reports the same set of official statistics, compiled the same way, from public records anyone can download. This page sets out where every figure comes from, what it does and does not mean, and how to reproduce it. Updated September 17, 2026.

The four datasets

What counts as a "town"

Nassau and Suffolk counties contain two cities, thirteen towns, nearly a hundred incorporated villages, and well over a hundred hamlets. Towns, cities and villages are governments with legal boundaries. Hamlets are not: a hamlet is an unincorporated community inside a town, with no government and no official line around it. For hamlets we use the Census Bureau's census-designated place (CDP), the standard statistical outline for the community, from the 2020 Census. Local usage of a hamlet's name — by the post office, a school district or residents — can cover more or less ground than its CDP.

Population, housing units and land area are the 2020 Census counts published with those boundaries [C]. Where a hamlet's CDP crosses a town line, the page reports the share of its area in each town.

Fatal crashes (2010–2024)

The Fatality Analysis Reporting System (FARS) is the National Highway Traffic Safety Administration's census of crashes on public roads in which a person died within 30 days. It carries no names or personal identifiers. We take every FARS crash coded to Nassau or Suffolk County — 3,099 crashes and 3,302 deaths over fifteen years — and assign each to the 2020 Census boundary that contains its reported latitude and longitude. A crash inside a village or hamlet therefore also counts toward the town that contains it.

• Unplaced crashes. 139 of the 3,099 crashes (4.5%) have no usable coordinates in FARS. They are counted in county totals but cannot be placed in a community, so community counts are slight undercounts for the early 2010s in particular (see the table below).
• Boundary roads. Many Long Island community lines run down the middle of a road. A crash there is assigned to whichever side its coordinates fall on.
• 2024 is preliminary. It comes from NHTSA's Annual Report File and is revised when the final file is released.
• Person types. Pedestrian, bicyclist and motorcyclist deaths are counted from the FARS person file (fatally injured persons by person type and vehicle body type).
• Alcohol is a floor, not an estimate. We count crashes in which a driver had a reported blood-alcohol concentration of .08 or higher. Many drivers are never tested; NHTSA's official alcohol figures impute those missing results and are higher than ours.
• Road owner has been recorded in FARS only since 2015, so ownership breakdowns cover 2015–2024.
• Road names are entered by police in many forms ("SR-27", "SUNRISE HWY"). We fold them into common names. Two cases need care: NY 24 is Hempstead Turnpike in Nassau but Flanders Road in Suffolk, and NY 27 is Sunrise Highway west of Shinnecock Hills and Montauk Highway east of it.

Rates are about residents, not risk

Pages give deaths per 100,000 residents per year so communities of different sizes can be compared. It is a resident-based rate. Crashes are counted where they happen, not where the people involved live, and we have no traffic-volume denominator at community level. A small village crossed by the Long Island Expressway will show a high rate that says little about its own streets. For that reason every page separates deaths on expressways and parkways from deaths on arterials and local streets. Island-wide, 477 of 3,302 deaths (14%) were on expressways or parkways; the rest were on ordinary roads. Pedestrians account for 1,009 deaths (31%). We do not rank communities as "most dangerous."

All reported crashes (2021–2024)

New York's Department of Motor Vehicles publishes a case-level file of police-reported crashes of every severity [D]. It codes each crash to a town, city or incorporated village — never to a hamlet, and it cannot distinguish a village from a town of the same name. So town, city and distinctly named village pages show their own counts, while hamlet pages (and the villages of Hempstead and Southampton) show the parent town's counts, labelled as such. The municipality is entered by the reporting police agency and is less consistent for small villages; we present these numbers as context and do not rank places with them.

Commuting (2020–2024)

Commute times, travel modes, departure times and vehicle access come from the American Community Survey 5-year estimates [B]. These are survey estimates, not counts. Every figure is shown with its 90% margin of error, calculated with the Census Bureau's formulas for derived proportions and ratios, and estimates whose coefficient of variation exceeds 30% are marked † as low-reliability. The Census Bureau did not publish 2020–2024 place-level estimates for the Brentwood or Wyandanch CDPs; those pages show the parent town instead and say so.

History, roads and law

The narrative sections are researched from primary and authoritative sources: municipal, county, state and federal records; court decisions with full reporter citations; the National Register of Historic Places; university and historical-society publications; and newspapers of record. Each sentence carries a numbered reference to the source it rests on. We do not cite Wikipedia or other encyclopedias, marketing sites, or content we cannot open and read. Where sources disagree, the page says so. We do not name crash victims or minors.

Before anything is published, a script re-fetches every cited page and checks that the researcher's supporting quotation is really there; claims whose sources cannot be confirmed are withheld, and an editor's decisions to correct or withhold material are logged. Court decisions are summarised from the opinion's own text. A summary describes the cited decision only: later appellate history is noted where we found it but has not been checked systematically, so confirm a case's current status with a citator before relying on it.

Reproducing the numbers

The statistics are built by four scripts (geography, commute, FARS, DMV) that download the public files above, with no API keys and no manual steps, and write the per-community JSON that these pages render. Each town page links its own machine-readable fact sheet (facts.json) and fatal-crash extract (fatal-crashes.csv).

Corrections and reuse

Send corrections to corrections@longislandtraffic.com with the page and the figure in question; fixes are dated. You are welcome to quote figures with credit and a link to the page they came from. See also our editorial policy.