Neighboring fast food restaurant advertisement signs in Bowling Green, Kentucky for Wendy's, KFC, Krystal and Taco Bell. A McDonald's sign can be seen in the very far background.
See also: Fast food restaurant § North America As automobiles became popular and more affordable following World War I, drive-in restaurants were introduced. The American company White Castle, founded by Billy Ingram and Walter Anderson in Wichita, Kansas in 1921, is generally credited with opening the second fast food outlet and first hamburger chain, selling hamburgers for five cents each.[25] Walter Anderson had built the first White Castle restaurant in Wichita in 1916, introducing the limited menu, high-volume, low-cost, high-speed hamburger restaurant.[26] Among its innovations, the company allowed customers to see the food being prepared. White Castle was successful from its inception and spawned numerous competitors.
Franchising was introduced in 1921 by A&W Root Beer, which franchised its distinctive syrup. Howard Johnson's first franchised the restaurant concept in the mid-1930s, formally standardizing menus, signage and advertising.[26] Curb service was introduced in the late 1920s and was mobilized in the 1940s when carhops strapped on roller skates.[27] The United States has the largest fast food industry in the world, and American fast food restaurants are located in over 100 countries. Approximately 5.4 million U.S. workers are employed in the areas of food preparation and food servicing, including fast food in the US as of 2018.[28] Worries of an obesity epidemic and its related illnesses have inspired many local government officials in the United States to propose to limit or regulate fast-food restaurants. Yet, US adults are unwilling to change their fast food consumption even in the face of rising costs and unemployment characterized by the great recession, suggesting an inelastic demand.[29] However, some areas are more affected than others. In Los Angeles County, for example, about 45% of the restaurants in South Central Los Angeles are fast-food chains or restaurants with minimal seating. By comparison, only 16% of those on the Westside are such restaurants.[30]