They were designed as a guide to tell drivers about eateries they recommended to visit and to subtly sponsor their tires, by encouraging drivers to use their cars more and therefore need to replace the tires as they wore out.
[1] Multiple anonymous Michelin inspectors visit the restaurants several times.
They rate the restaurants on five criteria: "quality of products", "mastery of flavor and cooking techniques", "the personality of the chef represented in the dining experience", "value for money", and "consistency between inspectors' visits".
[1][2] Inspectors have at least ten years of expertise and create a list of popular restaurants supported by media reports, reviews, and diner popularity.
If they reach a consensus, Michelin awards restaurants from one to three stars based on its evaluation methodology: One star means "high-quality cooking, worth a stop", two stars signify "excellent cooking, worth a detour", and three stars denote "exceptional cuisine, worth a special journey".