Data methodology
This page explains where the specifications, dates and figures in the 1cars car catalog come from, how we check them and what the labels next to them mean. It applies to model and generation pages, key facts boxes, specification tables and comparisons.
Where our data comes from
We prefer primary sources and record the source of each value in our catalog:
- Manufacturers: official press releases, technical specification sheets, owner’s manuals, brochures and price lists.
- Regulators and test bodies: type-approval and emissions data (WLTP, NEDC, EPA), safety ratings (Euro NCAP, IIHS, NHTSA) with the year of the test.
- Historic vehicles: factory documentation, museum and archive records and reference books; for cars built decades ago we rely on these instead of modern databases.
- Open reference data: structured data such as Wikidata helps us match models and generations, but a figure is not treated as confirmed on that basis alone.
Verified and unverified values
A value is verified when it is confirmed by a primary source or by two independent reputable sources. Values taken from a single secondary source are shown as unverified and marked as such in the key facts box. When we cannot confirm a figure at all, we leave it out rather than guess.
Units, markets and prices
- We give metric units first and imperial units in brackets: kW (hp), litres (cu in), kg (lb), km/h (mph), L/100 km (mpg US).
- Engine output is quoted as the manufacturer states it; figures can differ between markets and model years, and we name the market when it matters.
- Prices are given in euros, always with the year and the market they refer to. Old prices are shown for context only.
- Production years refer to the start and end of series production; a facelift is part of the same generation unless the manufacturer treats it as a new one.
How we define generations
We follow the manufacturer’s own generation codes (for example, chassis codes) where they exist. Some databases count facelifts or body variants as separate generations; we list them inside the generation they belong to.
Updates and corrections
Catalog data is reviewed when we rewrite or update an article, and the update date is shown on the page. If you find an error, use the “Report an error” link at the bottom of any article or our contact form. We check every report against the sources and correct confirmed errors.
More about how we work: editorial policy.
Where the figures in our catalog come from today
- Models
- 5,298
- Generations
- 2,387
- Versions
- 4,970
- Verified versions
- 4,328
The catalog holds 5,298 models, 2,387 generations and 4,970 versions, of which 4,328 versions are marked as verified. This table is generated from the catalog itself and updates as we add data.
| Source | What it gives us | In the catalog |
|---|---|---|
| 1CARS model articles | Version specifications taken from the specification tables and text of our own model articles | 638 versions |
| 1CARS editors | Version specifications entered or corrected by our editors against a named source | 3,072 versions |
| 1CARS editors | Model facts (years, country, body and fuel types) corrected against a named source, usually the maker or Wikipedia | 4,242 models and generations |
| Wikidata (CC0) | Matching of models and generations, production years and the maker’s country | 5,041 models and generations |
| Wikimedia Commons, Flickr, Unsplash, Pexels, makers’ press sites | Photos of cars that have no photo of their own, always with the author and licence (press photos: the maker) | 6,124 photos |
| FuelEconomy.gov (US EPA) | Official US fuel economy (mpg) of matching versions | 1,260 versions |
| European Environment Agency — CO₂ monitoring of new cars (CC BY 4.0) | Official EU WLTP CO₂, fuel or energy consumption and mass, filled in only where a version had no figure: the median of new EU registrations of the same model, fuel and power (±5 %), with the registration year | 449 versions |
| NHTSA (US) | Safety recall campaigns | 30 recalls |
| Euro NCAP | Crash-test star ratings with the year of the test | 286 generations |
| NHTSA 5-Star Safety Ratings — US NCAP (U.S. Government work, public domain) | US crash-test star ratings (overall score) for generations sold in the USA, always with the model year of the rating; not directly comparable with Euro NCAP | 168 generations |
| Makers’ price lists | New-car prices in euros, always with the year of the price | 67 prices |
When a page or a figure is published
- A version page (/specs/…) is opened to search engines only when at least 12 of its 25 specification fields are filled in, it names an external source and it has at least one performance, consumption or weight figure. A version that differs from a sibling in no more than one field stays out of the index and links to the sibling instead.
- A list of cars by body type, country or decade is published only with at least 6 models.
- A ranking appears only when at least 6 models have a figure, and is opened to search engines from 15 models. Each model is ranked once, with the best figure among its versions; figures outside a plausible range (for example a boot volume measured with the seats folded) are left out.
- A league on the Supercars page is shown only with at least 3 cars that have the figure.
- When a figure is missing, the block or row is hidden — we never estimate a value to fill a gap.
See how the rules work in practice in our car rankings by the numbers.