In the U.S. state of Arizona, Interstate 10, the major east–west Interstate Highway in the southern United States, runs east from California, enters Arizona and continues through Phoenix and Tucson and exits at the border with New Mexico.

Route description

The western terminus is located at the California border at the Colorado River in La Paz County where I-10 continues westward into California towards Los Angeles. Here, the same physical road is signed as both Interstate 10 and U.S. Route 95. The highway runs east by northeast past Ehrenberg and Quartzsite and then turns to an east by southeast orientation just before the junction for U.S. Route 60.

Papago Freeway

It continues this path entering Maricopa County and the Phoenix Metro area. The route turns east by northeast again at the junction for SR 85 northwest of downtown Buckeye, and turns due east at 203rd Ave/Tuthill Rd. The landscape by this point is largely urban and the freeway continues eastward through the communities of Goodyear, Avondale and Tolleson, meeting with area freeways such as Loop 303 and the western side of Loop 101 along the way.

Traversing through Phoenix, the highway meets with Interstate 17 for the first time just northwest of downtown at The Stack. Near 3rd Avenue, the highway enters a half-mile tunnel (800 m) that runs under a park and the central branch of the City of Phoenix Library. Emerging past 3rd Street, the highway continues due eastward for another before coming to another interchange for Route 51 and Loop 202, called the Mini Stack. At this interchange, Interstate 10 turns southward for about , passing near Sky Harbor Airport and reaching the second junction with Interstate 17. Here, I-17 and I-10 merge as I-10 skews eastward again. After this junction, the highway is signed as US 60 as well.

Maricopa Freeway

Continuing southeast over the Salt River and eastward, I-10 enters Tempe and meets with SR 143. Then, at the Broadway Curve, the freeway turns southward again, with US 60 splitting off to become its own freeway. I-10 continues southward running along the city borders of Phoenix on the west, and Tempe, Guadalupe, Tempe again, and finally Chandler on the east. Immediately north of the Gila River Indian Community, I-10 has its second intersection with Loop 202. Past Loop 202, the highway turns to a more south by southeast direction going through the Gila River Indian Community and entering Pinal County.

Pearl Harbor Memorial Highway

Interstate 10 in Arizona outside the Phoenix Metropolitan Area is referred as the Pearl Harbor Memorial Highway. In Phoenix, I-10 is referred as the Papago, Inner-Loop and Maricopa Freeway.

Annual Average Daily Traffic

Annual Average Daily Traffic (AADT) counts for Interstate 10 at the state lines and the cities it passes through in Arizona are listed below.

Exit	Location	2006 AADT	2007 AADT	2008 AADT
0	CA State Line	29,400	26,100	25,700
17	Quartzsite	23,600	20,200	17,400
120	Buckeye	54,600	61,800	59,100
135	Tolleson	138,000	185,000	128,000
146	Phoenix	291,000	288,000	256,800
155	Tempe	206,000	200,000	221,400
160	Chandler	116,000	116,000	112,800
198	Casa Grande	42,800	44,400	37,740
257	Tucson	169,000	176,000	178,300
303	Benson	17,000	16,900	16,600
340	Willcox	14,100	14,500	14,300
390	NM State Line	12,000	12,600	12,400

History

Interstate 10 in Arizona was laid out by the Arizona Highway Department in 1956-58 roughly paralleling several historic routes across the state. Particularly east of Eloy, it follows the Butterfield Stage and Pony Express routes, and loops south to avoid the north-south Basin and Range mountains prevalent in the state. In fact, the route from its junction with Interstate 8 east to New Mexico is almost exactly the same route used by the old horse-drawn stagecoaches, which had to go from waterhole to waterhole and avoid the hostile Apache Indians. This is why I-10 is more of a north-south route between Phoenix and Tucson than east-west. The Southern Pacific Sunset Route line had to take the route of least hills, and in the 1920s highways were laid down next to the trains across southern Arizona.

When the project was being designed in the 1950s, the Arizona Highway Department fought for a nearly straight-shot west from Phoenix for the new freeway, instead of angling northwest out of Phoenix along U.S. 60-70-89, through Wickenburg. Wickenburgers battled to bring the freeway through their city but lost that battle. The detour up through Wickenburg was logical decades earlier, when nearly all U.S. highways through Arizona were laid out along railroad tracks, and U.S. 60-70 was routed mostly parallel to the Santa Fe rail tracks east of Wickenburg, and the Arizona and California Railway west to Vicksburg. The two old federal routes then struck west across the desert and state line, picking up the Southern Pacific mainline at Indio, California, and I-10 overlies the old roads most of that distance.

Moving east from the California line at Ehrenburg, I-10 follows the old route of U.S. 60-70 for the first east from Blythe, California. In 1960, this western-most stretch of I-10 was built from near the Colorado River east to the future spot where the "Brenda Cutoff" section of I-10 would connect a decade later. Until the early '70s, this was the last freeway stretch until Phoenix. The "Brenda Cutoff" was named for a gas station on the old road just east of the fork where U.S. 60 now terminates at I-10. Now an obscure name, "Brenda Cutoff" was the working title that the Arizona Highway Department called the stretch of freeway from U.S. 60 to near Buckeye. The Brenda Cutoff paralleled old sand roads used in the 1920s for Phoenix-L.A. traffic, but mostly abandoned after U.S. 60-70 was built to the north, through Wickenburg.

The Brenda Cutoff's opening in the early 1970s was eagerly awaited and was a big deal in newspapers in Phoenix and Los Angeles. It saved motorists from having to drive through Glendale, Sun City, Wickenburg and Salome, out of the way, and it eliminated about of two-lane highway. But the freeway was opened only as far east as Tonopah, and heavy traffic was routed down narrow county roads through the desert and fields between Tonopah and Buckeye. In addition, there was only one very-small gas station on the very-long route between Buckeye and Quartzsite, on the old county road at the tiny crossroads of Palo Verde. Signs warning "NO SERVICES NEXT 106 MILES" were posted at either end of the Brenda Cutoff those first few years.

The freeway was extended past Tonopah as far east as Phoenix's western fringes in about 1974. I-10's freeway section ended in Goodyear until the controversial Papago Freeway was finished across the western Valley of the Sun in 1990. During the "west valley gap" years, westbound I-10 traffic was routed off the Maricopa Freeway at 19th Avenue in Phoenix, and stayed on the access road as it curved past the Durango Curve. Los Angeles-bound traffic then turned left on Buckeye Road and followed the "TO 10" signs down Buckeye Road (first marked U.S. Route 80 until 1977, then Arizona 85, for nearly 15 years.

The interstate's route through Phoenix was hotly contested in the 1960s, 1970s and early '80s. A plan proposed by the Arizona Department of Transportation involved monstrous block-sized 270-degree "helicoil" interchanges at Third Avenue and Third Street that would connect motorists to freeway lanes 100 feet (30 m) in the air, but voters killed it in 1973 as a result of opposition from the Arizona Republic newspaper and a growing nationwide anti-freeway sentiment. Voters on election day were treated to a photo depiction on the front page of the newspaper that in later years was shown to have drastically-overstated the freeway's height, but there is no question the proposed viaducts and helicoils would have been a visual gash across central Phoenix.

Beginning in 1961, a stub of what is now the route of Interstate 10 was built northward from the Maricopa Freeway (then Interstate 10) along 20th Street, ending 1/2 mile north at Buckeye Road. The I-10/I-410 interchange was the first multi-level interchange in Arizona and lasted until the Papago Loop was built as a real freeway in the 1980s. It was first posted as Interstate 410, then as Interstate 510. This putative freeway was two lanes in each direction and would have been hopelessly inadequate as a leg of the "Inner Loop" as it was intended. The spirit of Interstate 510 lives on as "Arizona 51," the section of freeway paralleling 20th Street north of the "Mini Stack" interchange with Interstate 10 and Loop 202.

After 1973, Arizona engineers favored a more-modest plan to link I-10 with Interstate 17 at the "Durango Curve" near 19th Avenue at Buckeye Road, and avoid the "Moreland Corridor" Papago Freeway alignment by adopting a route south of Buckeye road. Ten years later, ADOT unveiled the current below grade plans on Moreland Street, three blocks south of McDowell Road. Despite some local opposition, I-10 was finally completed in central Phoenix on the Papago Freeway alignment, 3/4 of a mile north of Van Buren Street, on August 10, 1990.The state is now considering a reliever west valley freeway, parallel to I-10 on the old Durango Street corridor, and is using the Route 801 symbol as a placeholder.

The original 1962 alignment of I-10 through Phoenix was on the Black Canyon and Maricopa freeways, now signed as I-17 and U.S. 60, starting at about Grand Avenue. From 1962-74, Interstate 10 in Phoenix ended at 40th Street, and truck traffic through Phoenix and Mesa was directed to use Arizona Route T-69 via 40th Street south and Baseline Road east to connect to state Routes 87 and 93, the shortcuts to Tucson. The 10 signs were moved from the Maricopa Freeway to the Papago Freeway Inner Loop alignment when it opened in 1990 - the last gap of I-10 to be completed between Santa Monica and Jacksonville. This was the only time in Arizona where the posted freeway was moved from one road to another: the state never posted Interstate signs on older state or U.S. highways... ADOT instead made frequent use of interstate shields with the word "TO" above and arrows below the shield.

For several years in the early '70s an orphan section of I-10 was opened between Baseline Road and Williams Field Road (now Chandler Blvd.) but was not marked as any highway, nor was it connected to the rest of the Interstate Highway System. ADOT, it seems, did not want to divert trucks down from T-69 in Guadalupe down into the cotton fields west of Chandler. This section got its interstate signs when the freeway south to Casa Grande was completed in about 1970, and the "Broadway Curve" was connected a year or so later -- for almost two years, I-10 traffic used Baseline Road and 40th Street through the Japanese flower gardens until the last link between Tucson and Phoenix opened in about 1972.

From 1958-1972, the interstate was unmarked south from Tempe and Mesa, and traffic used either State Route 87 through Coolidge or State Route 93 through Casa Grande, or U.S. 80/89 through Mesa and Florence. Interstate 10 signs reappeared at the town of Picacho, the 1962-1970 western terminus of the freeway from Tucson.

The road from Casa Grande to Tucson was originally Arizona routes 84 and 93, and when it was rebuilt as a freeway in 1961-62 it was cosigned as Interstate 10 and routes 84 and 93 through 1966, when 84 was truncated at Picacho. This section of interstate was completed in 1961, and forced the demolition of the town center at Marana, which has never really recovered. The freeway through Tucson (being rebuilt and widened from 2007 through 2009) was originally signed as State Route 84 from Miracle Mile to Sixth Avenue,

The original highway from Casa Grande to Tucson entered the Old Pueblo via Miracle Mile, a road modeled after German Autobahns but without overpasses or an exclusive right of way. Traffic circles at either end of Miracle Mile were the best Tucson could come up with in 1937. The section of Miracle Mile West stretching between Miracle Mile and the Southern Pacific overpass was signed as Business Loop 10, State Route 84A and State Route 93 in the 1960s. It is now marked as the southern leg on State Route 77, the new designation for US 80-89 north out of Tucson. The Business Loop was dropped in 1998, as many of the business entrepreneurs in the area were practicing a very-old roadside business indeed.

The present-day Interstate 10 alignment along the Santa Cruz River was laid out after a city bond issue passed in 1948 to build a riverbank-side boulevard with room for a four-lane freeway in the median to follow. The first section of bypass artery, from Congress Street north to Miracle Mile West, was opened in 1954 but had no overpasses or interchanges at Grant Road, Speedway Boulevard or St. Mary's Road. The freeway was finally built after the state took over the bypass and promised it interstate status in 1958, and parts of it obliterated the original road. It was first signed State Route 84.

The old cloverleaf at Sixth Avenue was the first built in Arizona, opening in the early 1950s as a southern Tucson gateway junction to the roads linking Tucson, Benson, Nogales and the hoped-for Tucson bypass along the Santa Cruz River. It was converted to a diamond interchange by 1964 and the old "quick dip" underpass was removed and replaced by an interstate-standard overpass in the late 1980s.

Although the controversial Interstate 10 route across Phoenix was the last gap of Interstate 10 to be completed, two pieces of the interstate were subsequently left sitting on divided remnants of old U.S. 80 and were neither built to interstate nor modern safety sections. One was the old Sixth Avenue interchange, and a small section of freeway east to the overpass over the old Southern Pacific (now UP) spur to Nogales and Guaymas. That section was replaced about 1990.

The last section of old U.S. 80 that carries the Interstate 10 traffic is an underpass beneath the Union Pacific mainline east of Tucson, where the freeway median shrinks to a guardrail at Marsh Station Road and the Pantano train overpass is too low. It is slated for replacement in 2010-2011.

East of Tucson, Interstate 10 parallels and in some cases overlies old U.S. 80 to Benson, and was originally co-signed as U.S. 80 and State Route 86. From Benson, the Interstate follows the Southern Pacific mainline east through Willcox and Bowie to New Mexico, rather than bend south to the Mexican border along old U.S. 80 (signed as State Route 80 after 1989), through Douglas. The road from Benson east through Willcox was designated State Route 86 in about 1935, that route number was subsequently shifted west and exists now between Why and Tucson. The bypass around Benson was opened about 1979, and other than the Phoenix gap was the last section of Interstate 10 to be opened.

The Arizona Department of Transportation in 2008 conducted a feasibility study of building new bypass freeways around Phoenix and Tucson and "straighten" Interstate 10 across the state. One route would have gone roughly from Buckeye east to Florence, then east through mountainous terrain to the Sulphur Springs Valley and connect with the existing Interstate 10 near Bowie. But this new roadway would traverse some environmentally fragile areas and was opposed as a gateway to urban sprawl. Another studied alignment would bypass Tucson to the south, forming a looping bypass freeway from Marana through the Avra Valley to Green Valley to Benson, an alternative that is still being studied.

Broadway Curve

As of a 2006 estimate, the Broadway Curve portion of I-10 in Tempe carries an average of 294,000 vehicles per day. This number is predicted to increase by over 150,000 to approximately 450,000 by the year 2025. This section of the Maricopa Freeway (Interstate 10) is currently twelve lanes wide; one of the widest sections of freeway in the valley. A study is underway to determine whether widening the Broadway Curve to double its current width to twenty-four lanes is feasible. The study should be complete in 2010, when a decision will be made.

Exit list

County	Location	Mile	#	Destinations	Notes
La Paz		0.72	1	Ehrenburg, Parker
		5.87	5	Tom Wells Road
		11.99	11	Dome Rock Road
	Quartzsite	17.54	17		East end of US 95 overlap
		19.94	19
		26.68	26	Golden Nugget Road
Maricopa		31.18	31
		45.38	45	Vicksburg Road
		53.98	53	Hovatter Road
		69.69	69	Avenue 75 East
		81.24	81	Salome Road
		94.18	94	411th Avenue - Tonopah
		98.32	98	Wintersburg Road
		103.47	103	339th Avenue
	Buckeye	109.70	109	Sun Valley Parkway, Palo Verde Road
		112.77	112	, San Diego
		114.88	114	Miller Road - Buckeye
		117.01	117	Watson Road
		120.24	120	Verrado Way
		121.72	121	Jackrabbit Trail
	Goodyear	124.73	124
		126.71	126	Pebblecreek Parkway, Estrella Parkway
		127.71	127	Bullard Avenue
		128.72	128	Litchfield Road - Goodyear
		129.71	129	Dysart Road
	Avondale	131.71	131	Avondale Boulevard
		132.69	132	107th Avenue	Westbound exit is via exit 133A
		133.69	133A	99th Avenue
	Tolleson	133.98	133B
		134.69	134	91st Avenue - Tolleson
		135.68	135	83rd Avenue
	Phoenix	136.18	136A	79th Avenue	HOV only; westbound exit and eastbound entrance
		136.70	136B	75th Avenue	Signed as exit 136 eastbound
		137.69	137	67th Avenue
		138.67	138	59th Avenue
		139.66	139	51st Avenue
		140.66	140	43rd Avenue
		141.67	141	35th Avenue
		142.67	142	27th Avenue	Eastbound exit and westbound entrance
		143.18	143		Signed as exits 143A (north) and 143B (south)
		143.89	143C	19th Avenue, Grand Avenue	westbound exit and eastbound entrance
		144.68	144A	7th Avenue	Signed as exit 144 westbound
		144.70	144B	5th Avenue; 3rd Avenue	HOV only; eastbound exit and westbound entrance
		145.46	145A	7th Street	Signed as exit 145 eastbound
		145.70	145B	3rd Street	HOV only; westbound exit and eastbound entrance
		146.71	146	16th Street	Eastbound exit and westbound entrance
		146.96	147A
		147.27	147B
		147.27	147C		HOV only; eastbound exit and westbound entrance
		147.27	147C		HOV only; westbound exit and eastbound entrance
		148.18	148	Washington Street, Jefferson Street	Airport rental car return, Phoenix light-rail station
		148.94	149	Sky Harbor International Airport (eastbound), Buckeye Rd (westbound)	Airport rental car return
		149.57	150A		West end of US 60 overlap; signed as exit 150 eastbound
		150.94	150B	24th Street	Westbound exit and eastbound entrance
		151.50	151	University Drive, 32nd Street
		152.39	152	40th Street
		153.38-153.75	153		Signed as exits 153A (SR 143) and 153B (Broadway Road, 52nd Street) westbound
	Tempe	155.25	154		East end of US 60 overlap; also includes HOV eastbound exit and westbound entrance
		155.94	155	Baseline Road
	Guadalupe	157.98	157	Elliot Road - Guadalupe
	Tempe	158.98	158	Warner Road
	Chandler	159.98	159	Ray Road
		160.98	160	Chandler Boulevard
		161.50	161
		162.82	162	Wild Horse Pass Boulevard, Sundust Road
		164.80	164	Queen Creek Road;
		167.78	167	Riggs Road - Sun Lakes
Pinal		176.11	175	, Casa Blanca Rd, Sacaton
		185.56	185
		190.95	190	McCartney Road – Central Arizona College, Casa Grande Regional Airport
	Casa Grande	195.19	194
		198.40	198	Jimmie Kerr Boulevard – Casa Grande
		199.36	199	, San Diego
	Eloy	200.40	200	Sunland Gin Blvd – Arizona City
		204.13	203	Toltec Road – Eloy
		209.09	208	Sunshine Boulevard – Eloy
		211.27	211A	Picacho Road – Arizona State Prison, Picacho	Eastbound exit only
		211.27	211B	Florence	Westbound exit signed as exit 211
		212.49	212	Picacho	Westbound exit only
		220.13	219	Picacho Peak Road – Picacho Peak State Park
		226.74	226	Red Rock
		232.30	232	Pinal Airpark Road
Pima	Tucson	236.71	236	Marana
		240.74	240	Tangerine Road
		243.24	242	Avra Valley Road
		247.02	246	Cortaro Road
		249.01	248	Ina Road
		250.35	250	Orange Grove Road
		251.47	251	Sunset Road
		252.71	252	El Camino del Cerro, Ruthrauff Road
		254.59	254	Prince Road
		255.57	255
		256.46	256	Grant Road
		257.61	257	Speedway Boulevard, (St. Marys Road) (eastbound) - University of Arizona
		258.65	258	Congress Street, Broadway Boulevard, (St. Marys Road) (westbound)
		259.63	259	22nd Street, 29th Street, Starr Pass Boulevard, Silverlake Road
		260.39	260
		261.28	261	6th Avenue, 4th Avenue	Former I-19 Business
		262.02	262	Benson Highway, Park Avenue	Former Interstate 10 Business
		262.86	263	Kino Parkway, Ajo Way - Tucson International Airport	Signed as exits 263A (south) and 263B (north) eastbound
		264.73	264	Palo Verde Road, Irvington Road	Signed as exits 264A (south) and 264B (north) eastbound
		265.32	265	Alvernon Way
		267.40	267	Valencia Road - Tucson International Airport	Former Interstate 10 Business
		268.39	268	Craycroft Road
		269.64	269	Wilmot Road
		270.87	270	Kolb Road
		273.43	273	Rita Road
		275.77	275	Houghton Road
		279.68	279	Wentworth Road, Vail Road
		281.96	281
		289.71	289	Marsh Station Road
		292.77	292	Empirita Road
Cochise		297.45	297	Mescal Road, J-6 Ranch Road
		299.63	299	Skyline Road
	Benson	302.67	302
		304.16	303		No westbound exit
		305.20	304	Ocotillo Street - Benson
		307.43	306
		313.56	312	Sibyl Road
		319.76	318	Dragoon Road
		323.39	323	Johnson Road
		332.41	331		West end of US 191 overlap
		337.69	336
	Willcox	341.33	340
		345.28	344
		353.19	352		East end of US 191 overlap
		356.77	355
		363.66	362
		367.60	366
		379.75	378
		383.14	382
		391.57	390	Cavot Road

References

External links

• Interstate 10 - Arizona (AARoads.com)
• Papago Freeway at arizonaroads.com