The metropolitan area of Phoenix in the U.S. state of Arizona contains one of the nation's largest and fastest-growing freeway systems, with over 1,405 lane miles (2,261 km) as of 2005 (this was before construction on the Loop 303 started).

All of Phoenix's state route and loop freeways are free roads, making it possible for them to still be assigned potential three-digit Interstate designations in the future, although no such plans are currently in place.

The highway serves Tempe, Guadalupe, Chandler, and the Ahwatukee neighborhood of Phoenix before meeting the Loop 202 for a third time on the border with the Gila River Indian Community.

While US 60 is co-signed with I-10 and I-17 through central Phoenix, it becomes a separate freeway in its own right on an east-west alignment between Baseline Road and Southern Avenue.

Known as the Superstition Freeway, this alignment serves major East Valley cities including Tempe, Mesa, Gilbert, and Apache Junction.

Along the way, it serves Glendale, Peoria, north Phoenix, Scottsdale, the Salt River Pima-Maricopa Indian Community, and Tempe.

[13] The Loop 303 is the second ring road for the Valley's northwest quadrant, extending from just south of I-10 in Goodyear to a temporary interchange with I-17 in far north Phoenix and serving outer Northwest Valley communities including Surprise, Sun City and Sun City West, and northern Peoria.

[15] To meet growing demand for a regional transportation link, an interim second phase, featuring an overpass over Ellsworth Road and continuing as a divided highway with at-grade intersections out to Ironwood Drive, was completed in 2022.

This freeway was formerly known as the Squaw Peak Parkway, but since "Squaw" is regarded as a derogatory term for Native American women, the Arizona Board of Geographic and Historic Names rechristened the mountain "Piestewa" Peak after Lori Piestewa, a Native American woman who died in the conflict with Iraq.

[19] A similar, though not identical path with high capacity lanes is being taken by the modern Northern Parkway (Arizona) which is being funded by Maricopa County and the associated cities adjoining the roadway.

Numerous Phoenix residents were opposed to SR 50's proposed route, and the number of homes that would be destroyed to create its necessary right-of-way.

The plans also had space for mass transit — either bus lanes or light rail (both at-grade and suspended underneath the freeway were presented as options).

Although the path was considered, studied, and put into some county highway plans, it never gained much traction and many transportation officials still believed SR 50 to be a better freeway option and possibility of it being built were removed along with the 50 in 1995.

In the early 2000s, several major six-legged intersections were eliminated along Grand Avenue in Phoenix, Glendale, and Peoria to improve traffic flow.

Complicating the design of these improvements and compounding the traffic woes they hoped to solve is the presence of the BNSF railroad, which closely parallels Grand to the south in Phoenix and Glendale and to the north between Peoria and Morristown.

The construction plan, which included a controlled-access intersection with Patterson Road and improvements to the junction with Route 238 in Gila Bend, was completed in 2010.

Interstate 11 is part of a long-range vision for the Valley's future transportation needs, as defined by the Maricopa Association of Governments and ADOT.

In June 2013, a joint draft study commissioned by the respective DOTs of Arizona and Nevada concluded that the freeway was justified, citing benefits in travel, tourism, trade, and economic growth.

Construction of the proposed Route 30 (former SR 801) has been approved, and will begin sometime in the early 2020s based on funding and planning by the Maricopa Association of Governments.

[26] Following the approval of Interstate 11 in the 2012 Surface Transportation Act, a study for a Westward extension of SR 30 to I-11 will be conducted by MAG.

Due to expected rapid growth in the northwestern reaches of the metropolitan area, long-term regional highway plans include acquisition of right-of-way for eventual future expansion of SR 74 to a freeway.

Phoenix has been expanding its highway system since 1985, when voters passed Proposition 300, which established a half-cent general sales tax to fund new urban freeways that were currently in the Regional Transportation Plan.

[33] In 1996, the Maricopa Association of Governments Regional Council passed a series of bills provided funding for a Long Range Plan between fiscal years 2007 and 2015.

[33] With the transportation tax set to expire in 2006, a revived Proposition 400 was put before the voters of Maricopa County in 2004, ten years after the original vote ended in failure.

[34] Unlike its predecessor, the proposition passed by a wide 58-42% margin and established funding for several future projects including highways and mass transit.

A similar but much more wide-reaching proposal to enact a full one-cent sales tax increase over a 30-year period on a statewide level, much of which would have gone to funding Phoenix area projects, failed to qualify for the 2008 general election ballot due to issues with the petition.

[35] However, the 1985 plan was not fully completed by 2007 due to the lingering unfinished segment of Loop 202 between University Drive and Power Road in Mesa, where work wrapped up on July 21, 2008.

Initially, these signs were only activated on weekdays during peak travel hours (6am to 9am and 3pm to 7pm) and did not appear if there is a more urgent message to display; such as an Amber Alert or other emergency.

Beginning in late 2013, several Phoenix area freeways began to receive logo signs at select exits, advertising food, lodging, gas, and attractions businesses.