How many freeways does Phoenix have? What to know about them

Madeline Nguyen, Arizona Republic
Updated ·6 min read

With one of the largest and fastest-growing freeway systems in the country, the metro Phoenix area — along with Arizona in general — is car country. Every year, Phoenix vehicles travel about 10 billion miles down its roads, including its extensive freeway system, highways and 1,168 miles of interstates.

As the fifth-largest city in the nation and one of its most rapidly growing, Phoenix is seeing only more and more drivers join its roadways each year. As a city that was designed around cars, Phoenix has its sprawling highway system at its heart. Here’s everything you need to know about the Valley’s highways.

How many freeways does Phoenix have?

Because Phoenix’s freeway system is divided into different segments, the exact number of freeways in the city depends on whether or not each segment is counted as its own freeway. If each major highway, rather than each segment, is taken as a freeway, there are eight freeways in Phoenix, according to Maricopa Association of Governments spokesperson Kelly Taft.

  • Interstate 10, which is divided into the Maricopa and Papago segments

  • Interstate 17, which is made up of the Black Canyon and Maricopa stretches

  • Loop 101, which may be subdivided into the Agua Fria, Price and Pima freeways

  • Loop 202, which is composed of the Red Mountain, San Tan and South Mountain segments

  • Loop 303, which is also known as the Bob Stump Memorial Parkway

  • U.S. Route 60, which is divided into the Superstition Freeway and Phoenix-Wickenburg Highway, or Grand Avenue stretches

  • State Route 51, which is also called the Piestewa Freeway

  • State Route 143, which is also known as the Hohokam Expressway

Difference between highway, freeway and interstate

Well, there’s less of a difference between these three terms than you may think. Even though all freeways and interstates are highways, not all highways are freeways and interstates. That’s because “highway” is an umbrella term referring to a public way that vehicles travel, according to the Federal Highway Administration.

Freeways and interstates are specialized types of highways. Of course, each freeway or interstate varies in design, funding and speed limits, but highways of the same type share some key commonalities.

Freeways are highways to which access to the route is controlled, meaning that drivers don’t take a hard turn to enter and exit them, such as through driveways or cross streets. Rather, vehicles smoothly access freeways through ramps, and they can cross them only through overpasses and underpasses. Often, freeways will feature medians to separate traffic headed in opposite directions.

You’ll typically find freeways in urban environments, and they’re usually governed by higher speed limits. Highways are not freeways when they contain traffic lights, feature pedestrian crossings or lack entrance and exit ramps.

To contrast, interstates are a specific category of highways that belong to the Interstate Highway System, a highway network that was created during the 1950s to facilitate transportation and commerce between the states.

The Interstate Highway System was created after President Dwight D. Eisenhower signed legislation authorizing its funding in 1956. During the 1950s, the federal government planned the Interstate Highway System and paid for the bulk of its construction.

To qualify for federal funding, interstates are held to higher standards, as they must be freeways, contain two lanes in each direction and follow strict rules regarding the width of the lanes.

What was the first freeway in Phoenix?

First built in 1956, the Black Canyon Freeway, which is a part of Interstate 17, was Phoenix’s first freeway.

The route’s first iteration was as a stagecoach line north of Phoenix. Today, it’s developed into a modern highway that serves as a direct route between Phoenix and Flagstaff. The freeway was completed 22 years after it was first built in northern Arizona in 1978.

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When were the Phoenix freeways built?

  • Black Canyon Freeway: Built 1956

  • Maricopa Freeway: Built 1958

  • Superstition Freeway: Opened 1971

  • Hohokam Expressway: Opened 1978

  • Papago Freeway: Built 1983

  • Agua Fria Freeway: Built 1987

  • Pima Freeway: Built 1987

  • Price Freeway: Built 1987

  • Bob Stump Memorial Parkway: Opened 1991

  • Piestewa Freeway: Opened 1991

  • Red Mountain Freeway: Opened 1993

  • SanTan Freeway: Built 1999

  • Gateway Freeway: Built 2012

What is the busiest freeway in Phoenix?

Many Phoenicians are no strangers to being stalled on the freeway in bumper-to-bumper traffic, but according to Vladimir Livshits, the director of transportation technologies and services at the Maricopa Association of Governments, one freeway is by far the busiest: Interstate 10.

In particular, Livshits highlighted the section of the I-10 between Seventh Street and 16th Street, which may see over 100,000 vehicles a day, as the busiest strip of freeway in Phoenix.

What is the longest freeway in Arizona?

With 391 mileposts in Arizona, the I-10 is the state’s longest freeway, according to Arizona Department of Transportation spokesperson Steve Elliott.

What is the shortest freeway in Arizona?

Mesa’s Gateway Freeway may be the shortest in the state right now, according to Elliott, but one day, it’ll be much longer. When the highway opened in 2014, it was only a mile-long strip of freeway. Since then, expansion work has elongated the highway, also known as state Route 24, to just over five miles.

While the expansion made the Gateway Freeway longer than the state’s next-shortest freeway, the less than five-mile-long Hohokam Expressway in Phoenix, Elliott said only one mile of state Route 24 technically meets the criteria to be considered a freeway.

This is because access to the expanded section of state Route 24 is not yet controlled, and it has stoplights, meaning that the Gateway Freeway is still technically the state’s shortest freeway, Elliott said. The highway still has a long way to go until it’s complete, but it’s planned that the Gateway Freeway will one day connect with the North-South Corridor route proposed for Pinal County.

The speed limit on Arizona freeways

On urban freeways in Arizona, the speed limit is 65 mph while on rural freeways, it’s 75 mph, according to Hertz.

Notably, the Department of Transportation announced in October that the speed limit on a stretch of the Interstate 17 south of Peoria Avenue would raised from 55 mph to 65 mph following public input and a study it commissioned. On all other interstates in Phoenix, the speed limit was at least 65 mph.

Per state law, the Department of Transportation must set speed limits for Arizona highways after conducting an “engineering and traffic investigation.”

Madeline Nguyen is a breaking news reporter for The Republic. Reach her at Madeline.Nguyen@gannett.com or 480-619-0285. Follow her on X @madelineynguyen.

This article originally appeared on Arizona Republic: Highways, freeways and interstates in metro Phoenix