Methodology

NHTSA Office of Defects Investigation: consumer complaints, safety recalls, formal investigations, and manufacturer technical service bulletins / warranty extensions. All four are self-reported to the federal government by owners, manufacturers, or NHTSA itself — not independently verified by Milemark.

Milemark does not synthesize a single A–F grade or reliability score for any vehicle. Complaint counts alone, without real sales or registration data behind them, can't reliably separate "actually unreliable" from "just sold in large numbers." Instead, every vehicle page is descriptive: what breaks, by which system, how often it's reported, at roughly what mileage, how severe, and what NHTSA has on file for recalls, investigations and safety ratings. You draw the conclusion; Milemark shows the record.

Where a vehicle can be sorted by "longest-lasting," that ranking is median reported mileage before its single most-common issue — not complaint volume. A model with too little data for a reliable mileage figure sorts to the end, never to the top or bottom by default, so missing data never reads as "goes forever" or "fails immediately."

Vehicles or figures with too few classified complaints behind them are left blank or marked as limited data, rather than shown with false confidence.

• Federal mileage-at-failure reporting dropped sharply after May 2021, so onset-mileage figures are stronger for 2010s vehicles than for newer ones.
• Complaints are self-reported, not a random sample — vehicles owned by more vocal or more online populations may be over-represented.
• Trim-level detail is not currently published: several manufacturers (notably Ford trucks and all Nissan models) don't encode trim in the VIN, and each page covers every model year and trim a model was sold with.