The National Highway Traffic Safety Administration is an agency of the US Department of Transportation. It sets vehicle safety standards, rates new cars and requires manufacturers to recall vehicles and equipment with safety defects. Its site is organised under Ratings, Recalls, Risky Driving, Road Safety and Vehicle Safety, and the recall search covers four kinds of product: vehicles, car seats, tires and equipment.
The recall pipeline explains the data. Owners file complaints, which join a public NHTSA database once personally identifying information is removed. The Office of Defects Investigation screens them, analyses petitions and opens investigations; an investigation closes with a recall recommendation or with no defect found. Most recalls are started by manufacturers themselves, and the remedy is a repair, a replacement, a refund or, rarely, a repurchase.
Ratings come from the New Car Assessment Program and its 5-Star Safety Ratings: frontal, side barrier, side pole and rollover tests. They are not all comparable in the same way. Frontal ratings compare only within one weight class, while side ratings compare across all vehicles, and some vehicles show Not Rated. The field documentation carries that rule, so a crash test column is not read across classes by mistake.