The RPTA was formed in 1985 as the result of Phoenix-area voters approving a one-half percent sales tax increase for expansion of the local freeway system, and for expansion of mass transit. Main article: Phoenix, Arizona public transport The city of Phoenix alone operates 73 percent of all Valley Metro routes (several of which also serve suburban cities). Some RPTA funding is used to augment service provided by the member cities (this is expected to increase over the next several years due to a 2004 voter approval of an extension to the original 1985 sales tax for transit funding). A few routes which operate within several member cities have their funding and operations shared between those cities. The RPTA operates a customer service, marketing and long-range transit planning operation from headquarters in downtown Phoenix which is shared among all Valley Metro member cities.

Circulator service in Glendale is operated by the city of Glendale directly, the Scottsdale Trolley circulators are contracted by the city of Scottsdale, and intra-city paratransit service in the cities of Glendale and Peoria are operated by the respective cities directly.

The two largest operators of bus service are the city of Phoenix and the Regional Public Transportation Authority (operating multi-city routes and services primarily in Mesa, Chandler, Gilbert, and Tempe). Each city appoints a representative to the RPTA board of directors, and a chairman, vice chairman, and treasurer are voted on amongst the board members for a one-year term. These cities have agreed to participate in Valley Metro as a unifying brand name to streamline service and reduce confusion among riders. Most services are separately funded and operated by individual cities and suburbs in the greater Phoenix region. Valley Metro is a membership organization. In 2022, the combined bus and rail system had a ridership of 16,625,900, or about 53,300 per weekday as of the fourth quarter of 2022. Within the system, it is divided between Valley Metro Bus, which runs all bus operations, and Valley Metro Rail, which is responsible for light rail operations in the Valley. The Valley Metro Regional Public Transportation Authority, more popularly known as Valley Metro, is the unified public brand of the regional transit system for the Phoenix metropolitan area.

Metro valley bus