Interstate 17



Interstate 17 is the main north-south freeway in Arizona, connecting Phoenix with Flagstaff. It is a heavily traveled, regional corridor that connects Interstate 10 with Interstate 40.


In Phoenix, it is the Black Canyon Freeway, and it is one of the older freeways in the area, completed in the early 1960s1. It leaves the urban area and enters the central Arizona desert, with a business loop serving Rock Springs/Black Canyon City.

After Arizona 69 splits off toward Prescott, Interstate 17 turns northeast and begins its ascent onto the Mogollon Plateau. This requires a significant elevation increase between the desert floor and the top of the plateau, and the views are rewarding. Interstate 17 traverses the Coconino National Forest for its remaining distance to Flagstaff, with a forest landscape that is significantly different from the desert below.

The freeway has two major connections to the famous Sedona area, via Arizona 260 near Camp Verde and Arizona 179 near Rimrock. Interstate 17 continues through national forest land until meeting Interstate 40, and the freeway ends at a recently reconstructed interchange. A surface street, Arizona 89A, continues north into the city center of Flagstaff.

Mileposting Interstate 17

Between Phoenix and the Arizona 69 split (Exit 262), the freeway replaces old Arizona 69. This is significant because the exit numbering scheme still follows the original mileage of that route. According to the Misc.Transport.Road FAQ (Marc Fannin) based on comments from Richard C. Moeur, "Until the mid-1980s Arizona used a special system for its mileage -- any route which did not enter Arizona from another state used the mileage of the route where its southern or western end was for its point of origin rather than zero (e.g.: If Route 2's southern end was at Route 1 and Route 1's mileage at the Route 1/Route 2 intersection is Mile 57, then Route 2's lowest-numbered milemarker would be Mile 57). Interstate 17 is a special case: Its exit numbers are actually those of the former longer routing of Arizona 69, which branched from U.S. 89 at Mile 201, since Interstate 17 and Arizona 69 were paired early. Arizona 69 has been truncated since the exits of Interstate 17 were numbered (see Arizona 69 (Alan Hamilton)). The exit numbers on Interstate 17 are not related to those of Interstate 19."

Planned Improvements

Phoenix officials agree that an expansion of the Black Canyon Freeway in the capital city is needed. The freeway, originally constructed between Jefferson Street and Northern Avenue with four lanes, was designed for 20,000 vehicles per day (vpd). The same highway now carries up to 220,000 vpd amid six through lanes and two HOV lanes. The freeway is home to routine traffic back-ups.

To mitigate these traffic woes, ideas for expansion of the facility are included in the Maricopa Association of Government's 20-year Regional Transportation Plan. $1 billion in funds are earmarked for Interstate 17 in the plan. One of the concepts to address the issue of expansion is the creation of an Interstate 17 upper deck. The idea is not original, as many freeways in California, including Interstate 880/Cypress Street Viaduct, utilize this same format.

The Interstate 17 plan gets its inspiration from the Tampa, Florida construction of a second deck for Florida Toll 618, the Leroy Selmon Expressway. This east-west tollway will see the $350 million construction of a six-mile cantilevered second level, based upon centerline single pier-supports. In Phoenix, the second deck of the Black Canyon Freeway is considered for the stretch between Interstate 10 (Exit 199) north to Dunlap Avenue (Exit 207), a distance of eight miles.

The roadway would carry "Express" lanes, with only a few selected entry/exit points. Reasoning for this facility concept stems from the fact that the surrounding areas are densely developed with little room to expand outward. Some early public comments on the project have been positive. A west Phoenix community group, Community Leaders Organizing for Urban Transformation (CLOUT), are not supporters however. They contest that the highway would help divide west Phoenix from the rest of the city; they would rather see the $1 billion in funds allocated for mass transit-based projects.

Either way, the $15.7 billion Valley-wide transportation plan goes to a county wide vote May 18, 2004. Approval will mean an extension of the half-cent sales tax in Maricopa County beyond 2005.2 Construction of the upper deck for Interstate 17 will not likely occur until between 2016 and 2020 if approved.1

This map shows Interstate 17 as it enters the Phoenix Metropolitan area. A $15.7 billion plan to improve Phoenix area highways and mass transit goes to Maricopa County-wide vote May 18, 2004. Included is money for a new freeway from southwest Phoenix to Buckeye, funding for the South Mountain Freeway (Arizona Loop 202), and monetary allocation for a potential double-decking of Interstate 17 and extension of Arizona Loop 303 in Goodyear.2

Future Aspirations

According to the journal Roads and Bridges, Interstate 17 could be considered for an extension described as follows: "Interstate 17 -- Phoenix to Salt Lake City: Like Phoenix, Salt Lake City is one of the nation's fastest growing metropolitan areas with a population of 1.2 million. There is no direct Interstate connection between Phoenix and Salt Lake City. Completion of this corridor would require building or upgrading approximately 300 miles of roadway from Flagstaff, Arizona, to Sevier, Utah."

Interstate 17 is completed from Phoenix to Flagstaff, while Interstate 70 and Interstate 15 would complete the connection to Salt Lake City. The costs to construct this route, both economic and environmental, would be significant. Such an extension is way out in the future, as Arizona DOT is not even thinking about such a highway at this time.

Highway Guides

Southern Terminus - Interstate 10 - Phoenix, Arizona
Perspective from Interstate 17 south
The final four exits along southbound Interstate 17 are: Exit 195B, 7th Street; Exit 195A, 16th Street; and Exits 194B-A, Junction Interstate 10. This is the first mention of the southeastern interchange with Interstate 10 on a guide sign. These exit numbers are based on the mileage of former Arizona 69, so they do not end at milepost zero in Phoenix. This causes some confusion, but most here understand that Mile 194 is the south end of Interstate 17. Photo taken 01/17/05.
These are the last reassurance shields along southbound Interstate 17 and eastbound U.S. 60 before meeting Interstate 10 southeast of downtown Phoenix. Photo taken 10/27/03.
Southbound Interstate 17 and eastbound U.S. 60 approaches Exit 195A, 16th Street (last exit southbound) followed by its second and final junction with Interstate 10 in one mile. Photo taken 01/17/05.
The final exit along southbound Interstate 17 and eastbound U.S. 60 is Exit 195A, 16th Street. The final offramp, which connects southbound Interstate 17 with northbound (westbound) Interstate 10 to Sky Harbor International Airport at Exit 194, approaches. Photo taken 01/17/05.
The connection from southbound Interstate 17 and eastbound U.S. 60 to westbound Interstate 10 and Sky Harbor International Airport is via Exit 194 in the right lanes. The left lanes default onto eastbound Interstate 10 and U.S. 60. Photo taken 01/17/05.
Interstate 17 ends at its second interchange with Interstate 10; although signed as southbound, Interstate 17 is headed due east at this point. Westbound Interstate 10 leads north to Sky Harbor International Airport and downtown Phoenix. Eastbound Interstate 10 and U.S. 60 lead south to Tempe and southeastern Phoenix, with connections to Mesa, Globe, and Apache Junction via U.S. 60 and Tucson via Interstate 10. Photo taken 01/17/05.
An END shield is posted for the southern terminus of Interstate 17 as southbound merges onto eastbound Interstate 10. (There use to be an END shield at the north end of Interstate 17, but it was taken down when the Flagstaff interchange with Interstate 40 was reconstructed.) This shield was the only remaining end sign or shield posted on any of the Arizona statewide Interstates. Photo taken 01/17/05.
Perspective from Interstate 17 north
The first northbound Interstate 17 reassurance shield and associated U.S. 60 overlap. The two routes coincide with one another through to Exit 201/Grand Avenue. There U.S. 60 travels surface streets for the first time in Phoenix en route to Glendale, Peoria, Surprise and ultimately Wickenburg and the southern terminus of U.S. 93. Else wise Interstate 17 will again interact with Interstate 10 in approximately five miles. Photo taken by Justin Cozart (10/02).
Perspective from Interstate 10 west
The first indication of the upcoming Interstate 17 southern terminus is this Exit 150A overhead, 1.50 miles to the east. Due to the tunnels of Interstate 10 north of Downtown, Hazardous Cargo is relegated to Interstate 17 on the southside of the central business district. Photo taken 05/24/03.
Westbound Interstate 10 expands to seven lanes in preparation for the split with Interstate 17 north/U.S. 60 west. Exit 150B comes into play with 24th Street before the Interstate 17 terminal. Photo taken 01/17/05.
Auxiliary overhead for Exit 150B reminding motorists to use Interstate 17 for U.S. 60 based traffic interests to the northwest. Incidentally, U.S. 60 is the last remaining US route within the Phoenix metropolitan area. Gone are U.S. 70, U.S. 80, U.S. 89, and Arizona 93 (was it to be future U.S. 93 at one time?). Since most of these routes all shared the same road (Van Buren Street), it was much easier to turn back most of these routes. Photo taken 05/24/03.
Interstate 17 begins and U.S. 60 bids Interstate 10 farewell in this eight lane freeway scene along westbound. Also to the right Exit 150B departs for 24th Street. The first Interstate 17 interchange serves 16th Street, a short distance beyond this partitioning. Photo taken 01/17/05.
Here is another view of the same sign bridge, taken a couple years prior. Note that although the signs here were installed just three years ago, the top of the Exit 150B panel is missing. Photo taken 05/26/03.
The previous incantation of Interstate 10/17 guide signs on the above Pictured sign bridge. Note that Interstate 10 was cosigned with an Arizona 51 trailblazer and given the second control point of Central Phoenix. Photo taken by Patrick Sadler (1994).
The last sign bridge of this interchange is here, with the left four lanes continuing northwest on Interstate 10 toward Sky Harbor International Airport and Arizona 51/Piestewa Freeway. The right three lanes transition onto northbound (westbound) Interstate 17 and U.S. 60. The next Interstate 10 interchange is with Buckeye Road, one half mile to the north. The control city of Los Angeles, California is an additional 419 miles to the west along Interstate 10. Photo taken 01/17/05.
Perspective from Interstate 10 east
This is the first indication along eastbound (southbound) Interstate 10, just prior to the airport exit east of downtown Phoenix. Photo taken 01/17/05.
The right lane exits to Exit 150, Junction Interstate 17 north and U.S. 60 west. Note that U.S. 60 is omitted to alleviate confusion with the Superstition Freeway interchange. Photo taken 01/17/05.
Eastbound Interstate 10 approaches Exit 150, Junction Interstate 17 north. Interstate 10 and Interstate 17 form an inner belt surrounding downtown Phoenix. Photo taken 01/17/05.
A quarter mile further south, eastbound Interstate 10 reaches Exit 150, Junction Interstate 17 north. This interchange marks the southern end of Interstate 17. Photo taken 01/17/05.
Northern Terminus - Interstate 40 - Flagstaff, Arizona
Perspective from Interstate 17/Arizona 89A north
Interstate 17 northbound, two miles south of Exit 340A/B - Interstate 40. This is one of five Flagstaff area interchanges: Exit 333/Kachina Boulevard, Exit 337/Flagstaff Airport, Exit 339/Lake Mary Road, Exit 340/Interstate 40 and Exit 341/McConnell Drive. Photo taken 05/24/03.
With the San Francisco Mountains on the horizon, Interstate 17 draws to within one mile of the terminal interchange with Interstate 40. This sign retains button copy lettering. Photo taken 05/24/03.
Interstate 17 northbound expands to three lanes with the approach to Exit 339/Lake Mary Road to Mormon Lake. The stack interchange with Interstate 40 is 0.75 miles to the north. Photo taken 05/24/03.
Exit 339 departs as Interstate 17 nears Interstate 40. The interchange and northernmost reaches of Interstate 17 were recently reconstructed to expand capacity and allow for higher speed ramps between I-17 and Interstate 40. Photo taken 05/24/03.
Exit 340A leaves Interstate 17 northbound for Interstate 40 east. While the control city is Albuquerque, Interstate 40 also serves the Arizona towns of Winslow at Exit 252, Holbrook at Exit 285, and Chambers at Exit 333. Photo taken 05/24/03.
Results of the aforementioned construction project culminate with this high flyover from Interstate 40 west to Interstate 17 south. A cloverleaf ramp facilitates the traffic movements to Interstate 40 westbound from Interstate 17 north via Exit 340B. Interstate 40 travels 30 miles to Williams, 147 miles to Kingman, and 177 miles to Bullhead City via a connection with U.S. 93 and Arizona 68. Photo taken 05/24/03.
Situated just north of the Interstate 40 stack interchange, Exit 341 serves McConnell Drive and the city of Flagstaff. Arizona 89A continues north into downtown Flagstaff, where it terminates at Business Loop I-40 and U.S. 89. Photo taken 05/24/03.
Although Interstate 17 is not shown as continuing north along Arizona 89A via Interstate 40 signage, the next exit north of Interstate 40 (the last exit overall) carries the numbering convention of Interstate 17. Downtown Flagstaff is ahead. The mountain city is home to 52,894 Arizonans. Photo taken by Justin Cozart (10/02).
The northern terminus of Arizona 89A at Business Loop 40 (original U.S. 66) and the southern terminus of U.S. 89. U.S. 180 is located nearby. The stem of U.S. 80 represents the main highway into the Grand Canyon National Park area. Page is the control point of U.S. 89. This town is located far to the north near Glen Canyon Dam and the Utah state line. Photo taken 05/24/03.
Perspective from Arizona 89A south
Eastbound on Forest Meadows Street at Milton Road. Arizona 89A continues northward from the northern terminus into Flagstaff, where it meets Business Interstate 40 and U.S. 80. Interstate 17 is located to the right of this intersection. Photo taken by Jim Mullady (01/01).
Business Loop I-40/Historic U.S. 66 eastbound at the northern terminus of Arizona 89A. Arizona 89A begins the freeway spur that becomes Interstate 17 southbound to the right. To the left, Business Loop I-40 unites with the northbound beginning of U.S. 89 along Milton Road. Photo taken 05/24/03.
Nearing Exit 340B/A on Interstate 17/Arizona 89A southbound for Interstate 40. This interchange was recently under construction, with the addition of a new flyover between Interstate 40 west to Interstate 17 south. The City of Angels is approximately 462 miles to the west of Exit 340B. Photo taken by Justin Cozart (10/02).
The scene in the above photograph, during interchange reconstruction. The button copy panels in this photograph were replaced upon completion of the project with those in the above photograph. The Arizona control points of Williams and Winslow were eliminated from the sign convention. Photo taken by Jonathan Osborne (7/99).
Snow adorns the hillside in this perspective of the southbound Interstate 17 beginning at the Interstate 40 interchange. Photo taken by Jim Mullady (1/01).
Southbound Interstate 17/Arizona 89A at the cloverleaf off-ramp for Interstate 40 east/Exit 340A. Not as far as the westbound control city for Interstate 40, Albuquerque is still a fair distance away at 323 miles. The irony in this is that in Albuquerque the westbound control city of Interstate 40 is the 20,000 populous city of Gallup, not Flagstaff. Photo taken by Justin Cozart (10/02).
Perspective from Interstate 40 west
Interstate 17/Arizona 89A junction sign, five miles east of the northern terminus near Exit 201/U.S. 180 east. U.S. 180 overlaps with Interstate 40 from Holbrook at Exit 285 westward to Exit 201 at Flagstaff. Photo taken 05/24/03.
Two mile guide sign on Interstate 40 westbound for Interstate 17/Arizona 89A/Exit 195. Somewhat typical in many two mile advance signs on the Interstate system for Interstate junctions, no control cities are placed. Photo taken by Justin Cozart (10/02).
This near dusk photograph of the same sign reveals the reflectivity of the button copy lettering due to the camera flash. This is the last Interstate junction along westbound Interstate 40 until the highway terminates at Interstate 15 at Barstow, California, 352 miles to the west. Photo taken 05/24/03.
Nearing Exit 195/Interstate 17/Arizona 89A on Interstate 40 westbound, downtown Phoenix is 140 miles to the south. Sedona (via Arizona 89A south) is nestled 32 miles to the southwest. Photo taken by Justin Cozart (10/02).
Another dusk view of Interstate 40 westbound as it nears Interstate 17. Interstate 40 sees an additional two Flagstaff area interchanges after Interstate 17: Exit 192/Dairy Road and Exit 191/Business Loop I-40/West Flagstaff. Photo taken 05/24/03.
Interstate 40 splits with Exit 195 traffic for Interstate 17/Arizona 89A in this scene. A new flyover is in place for movements between Interstate 40 west to Interstate 17 south. Therefore all traffic now departs here instead of partitioning between here and a cloverleaf ahead. Photo taken by Justin Cozart (10/02).
A revisit to the Interstate 40/Exit 195 lane expansion. Arizona 89A reunites with its state route parent Arizona 89 near the town of Prescott 91 miles to the southwest. Arizona 89 emerges along original U.S. 89 at Interstate 40 Exit 146/Ash Fork. Photo taken 05/24/03.
Nearing the gore point for Exit 195 on Interstate 40 westbound. Interstate 17 lowers from an elevation of 6,910 feet here at Flagstaff to 1,090 feet at the capital city of Phoenix. Photo taken 05/24/03.
Continuing along the exit 195 off-ramp, drivers partition into the movements for Interstate 17 & Arizona 89A south to Phoenix and Arizona 89A (Milton Road) north to Northern Arizona University and the city of Flagstaff. Photos taken by Justin Cozart (10/02).
The original configuration of the southbound beginning of Interstate 17 from Interstate 40 west consisted of a cloverleaf ramp. This photograph shows the Interstate 17 southbound beginning and associated signage (including the still designated U.S. 89) at that original ramp. Photo taken by Michael Summa (1988).
Perspective from Interstate 40 east
Interstate 40 eastbound at the terminus of Interstate 17. U.S. 89A, which has since been downgraded to Arizona 89A, overlaps with Interstate 17 from Flagstaff southward. Photo taken by Bill Manning (08/78).


  1. "Double deck urged for I-17 in Phoenix." The Arizona Republic, September 16, 2003.
  2. "$15.7 billion transit plan endorsed." The Arizona Republic, September 18, 2003.

Page Updated May 28, 2005.

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State Arizona
Mileage 145.76
Cities Phoenix, Flagstaff
Junctions Interstate 10, Interstate 10, Interstate 40
Source: December 31, 2014 Interstate Route Log and Finders List
Interstate 17 Annual Average Daily Traffic

State Location AADT Composite Year
Arizona Phoenix 222,324 2001
Arizona North Phoenix 14,099 2001
Arizona Flagstaff 38,019 2001
Source: 2001 Arizona Interstate Annual Average Daily Traffic (AZDOT)
Complete Interstate 17 AADT data.