Data sources

• NHTSA vPIC: makes, models and model years.
• EPA fueleconomy.gov: engines, transmissions, drive types and fuel economy. Horsepower comes from the EPA's "Data on Cars Used for Testing Fuel Economy" files.
• Transport Canada, Canadian Vehicle Specifications (via NHTSA): exterior dimensions and curb weight.
• NHTSA recalls, complaints and NCAP crash-test APIs.
• ANKUSI Wheel Fitment Dataset: bolt pattern, center bore and factory wheel sizes, licensed under CC BY 4.0. Where a year has no record of its own, the value is carried across a generation only if every record in that generation agrees, and the page says so.
• OEM documents: owner's manuals (Toyota, GM, Honda, Mopar), Ford and GM towing guides, GM TechLink oil-capacity charts, Ford, Honda and FCA/Stellantis spec sheets, and parts catalogs. Each value cites the document and page, with a verbatim quote shown when you hover over the link.
• Third-party references (labelled): wiper-maker fitment lookups, tire-pressure and enthusiast reference sites, and battery-size lookups. Battery group sizes from these sources are labelled low confidence.

The data is rebuilt from these sources by an automated pipeline with quality checks before every site build.