These are the 19 most reliable used cars of 2018

• J.D. Power released its 2018 US Vehicle Dependability Study in February.
• The study measures car reliability by surveying respondents who have owned 2015 model-year vehicles for three years.
• Toyota won six categories, the most of any automaker, while General Motors came in second by winning five categories.

The used car market can be difficult to navigate. Sometimes, it's tough to tell if a seller is unloading a car because it's time for an upgrade, or because it's underwhelming.

J.D. Power helps shed some light on that question with its annual vehicle dependability study, which measures how much customers like their cars over time. This year's survey, which was released in February, collected feedback from 38,896 respondents who had owned a 2015 model-year vehicle for three years and determined the most reliable cars in 19 categories. The resulting data was used to determine the number of problems experienced per 100 vehicles. The lower the score, the more reliable the car is.

Toyota won six categories, the most of any automaker, while General Motors came in second by winning five categories.

These are the winners in each of the 19 categories.

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Small car: 2015 Kia Rio

Small premium car: 2015 Lexus CT

Compact car: 2015 Toyota Prius