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".
Unlike the other U.S. guides which focus mainly in the city proper, the San Francisco guide includes all the major cities in the Bay Area: San Francisco, Oakland, San Jose and Berkeley, as well as Wine Country, which includes Napa and Sonoma.
[8] The 2007 to 2018 Michelin Guides cover the San Francisco Bay Area & Wine Country.