Interstate 8 | |||||||
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Route information | |||||||
Length: | 348.25 mi[1] (560.45 km) | ||||||
Existed: | 1964 – present | ||||||
Major junctions | |||||||
West end: | Sunset Cliffs Boulevard in San Diego, CA | ||||||
I-5 in San Diego, CA |
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East end: | I-10 near Casa Grande, AZ | ||||||
Highway system | |||||||
Main route of the Interstate Highway System
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Interstate 8 (I-8) is an Interstate Highway in the southwestern United States. It runs from the southern edge of Mission Bay at Sunset Cliffs Blvd, in San Diego, California, almost at the Pacific Ocean, to the junction with Interstate 10, just southeast of Casa Grande, Arizona.[2] In California, especially from eastern San Diego County to points east, Interstate 8 runs very close to the United States-Mexico border where high-voltage transmission line Path 46 links Southern California to Mexico. At points in eastern Imperial County, the border is no more than half a mile (1 km) south of the Interstate.
I-8 at the Mountain Springs/In Ko Pah grade is routed down two separate canyons, as the freeway descends 4,000 vertical feet in 11 miles. This is one of the widest medians on the entire Interstate Highway System. In places, the median is over 1.5 miles (2.4 km) wide. I-8 also has the lowest above-ground elevation of any interstate at 52 feet (16 m) below sea level near El Centro, California. (The lowest point on the entire interstate highway system is in the Fort McHenry Tunnel while crossing under the Inner Harbor of Baltimore, Maryland on I-95. The highway bottoms out at −107 feet (−32.6 m).)
Contents |
mi | km | |
---|---|---|
CA | 169.92 | 273.46 |
AZ | 178.33 | 286.99 |
Total | 348.25 | 560.45 |
I-8 is part of the California Freeway and Expressway System[3] and is eligible for the State Scenic Highway System,[4] though it is not an official state scenic highway.[5] It is officially known as the Border Friendship Route from San Diego to the Arizona state line.[6] It is also signed as the Ocean Beach Freeway west of Interstate 5 and as the Kumeyaay Highway (after the local Native American tribe) for the entire length within San Diego County.
Interstate 8 begins at the intersection of Sunset Cliffs Boulevard and Nimitz Boulevard. For its first few miles, it parallels the San Diego River Floodway east. Near Old Town, I-8 intersects with Interstate 5 as well as with the former State Route 209. I-8 continues eastward, bisecting the area known as "Hotel Circle." As I-8 enters Mission Valley, it has junctions with State Route 163, Interstate 805 (Jack Schrade Interchange), and Interstate 15 and its continuation, State Route 15. In La Mesa, I-8 interchanges with State Route 125. I-8 continues into El Cajon, where it intersects with State Route 67 before it ascends into the mountains and the Cleveland National Forest, traveling through towns such as Alpine and Pine Valley. I-8 intersects with State Route 79 in the national forest before descending into the Imperial Valley and passing through the La Posta and Campo Indian reservations. In Boulevard, I-8 intersects with the eastern end of State Route 94.[7][8]
Interstate 8 straddles the San Diego-Imperial county line for a few miles before turning east. While going over the mountain pass into the Imperial Valley, I-8's roadways are separated by a considerable distance. This is because the eastbound lanes traverse the pass on the former roadbed of US-80. The westbound lanes were placed on a different routing. In the Imperial Valley, I-8 intersects with State Route 98, a highway leading to Calexico. I-8 then goes through Coyote Wells before entering the city of El Centro several miles later. In El Centro, I-8 intersects with State Route 86 and State Route 111, both north–south routes which connect to Interstate 10 in the Coachella Valley (north of the Salton Sea), before State Route 115 and State Route 98 merge with I-8. The freeway then traverses the Imperial Sand Dunes Recreation Area and intersects with State Route 186 leading to Mexico. Interstate 8 then passes through Felicity, California and Winterhaven before crossing the Colorado River into Yuma, Arizona[7][8] on a bridge built in 1978.[9]
I-8 enters Arizona from California at the Colorado River bridge at Yuma. It initially heads south through Yuma until the interchange with US 95 where the freeway begins to make the turn to the east. I-8 closely follows the alignment of the old US 80 route and in some locations, the US 80 alignment was upgraded and became I-8. West of Wellton, the highway curves towards the north to take a northeasterly course. Through this part of Arizona, I-8 passes along the northern edge of the Barry M. Goldwater Air Force Range and to the south of the Yuma Proving Ground. It keeps a northeastern heading until it reaches Gila Bend, Arizona where it intersects SR 85 which leads to Phoenix. After leaving Gila Bend, I-8 takes a southeastern heading as it passes through the Sonoran Desert National Monument. After exiting the monument, the highway continues on an easterly heading to a junction with SR 84 that will parallel I-8 to the north and go through Casa Grande while I-8 will pass to the south of the city. I-8 reaches its eastern terminus at an interchange with I-10 which continues on to Tucson.[10][11]
I-8 was part of the original 1957 plan of Interstates, following US-80 from San Diego to Gila Bend, Arizona, then AZ-84 from there to Casa Grande.
Interstate 8 replaced California's section of U.S. Route 80, which had existed from around 1929 until 1964. The original designations of US-80 in California were as LRN 12 (since 1909) from San Diego to El Centro, and as LRN 27 (since 1915) from El Centro to Arizona. I-8 was accepted as a chargeable interstate in 1957,[9] and was signed as Interstate 8 in 1964.[12] The "Ocean Beach Freeway" section west of I-5 was completed by 1967[13] as LRN 286 and was later designated as SR 109; it was later added to Interstate 8 in 1972.[9]
The portion of the route of I-8 between Yuma and Gila Bend was originally part of the proposed state system of highway in 1921.[14] In 1926, this section became part of the cross-country highway US 80. The route was not paved at this time, but was a gravel road along the entire corridor.[15] In 1928, the portion of I-8 between Gila Bend and Casa Grande was designated as SR 84.[16] By 1929, a small portion of the highway was paved near Yuma and SR 84 was under construction.[17] By 1930, SR 84 was completed, but not paved and the segment of US 80 between Astec and Sentinel had been paved.[18] By 1931, the entire portion of the highway under the US 80 designation had been paved.[19] Paving of the SR 84 had commenced by 1934, with the portion of the highway in Maricopa County being paved.[20] By 1935, the entire future corridor of I-8 had been paved from Yuma to Casa Grande.[21]
With the coming of the Interstate Highways, the corridor was to be upgraded to Interstate standards. By 1963, this process was in progress with portions of the highway between Mohawk and Gila Bend, and between Gila Bend and Stanfield having been upgraded.[22] By 1971, I-8 was nearly complete including a new alignment east of Yuma built parallel and to the south of the original US 80 alignment. A new alignment was also built to the south of the SR 84 alignment at the eastern end of the highway from southwest of Stanfield to the eastern terminus at I-10 southeast of Casa Grande. The only portions of I-8 not completed at this time were the Casa Grande bypass and the western end near Yuma.[23] As the Interstate was completed, the highways that it replaced were removed from the state highway system. In 1973, the SR 84 designation was removed from the highway from Gila Bend to the split where I-8 followed a new alignment southwest of Stanfield.[24] In 1977, the US 80 designation was removed from this stretch in favor of I-8.[25]
County | Location | Postmile [26][27][28] |
Exit [29] |
Destinations | Notes |
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San Diego SD T0.41-R77.77 |
San Diego | T0.41-T0.47 | Nimitz Boulevard, Sunset Cliffs Boulevard – Mission Bay Park | At-grade intersection | |
L1.21 | 1 | Mission Bay Drive, Sports Arena Boulevard to I-5 south | Westbound exit and eastbound entrance | ||
L2.38 | 2 | I-5 south (San Diego Freeway) – Downtown San Diego | No access from I-8 west to I-5 south and I-5 north to I-8 east | ||
L2.38 | 2A | I-5 north (San Diego Freeway) – Los Angeles | Westbound exit and eastbound entrance; no access from I-8 east to I-5 north and I-5 south to I-8 west | ||
2B | Rosecrans Street | Westbound exit and eastbound entrance; former SR 209 south | |||
R0.36 | 2C | Morena Boulevard | Westbound exit and eastbound entrance | ||
0.95 | 3 | Taylor Street, Hotel Circle | |||
2.23 | 4A | Hotel Circle | Westbound exit is via exit 3 | ||
2.41 | 4 | SR 163 (Cabrillo Freeway) / I-5 north – Escondido, Downtown San Diego | Signed as exits 4B (CA-163 south) and 4C (CA-163 north to I-5 north) eastbound and exits 4A (CA-163 south) and 4B (CA-163 north) westbound | ||
3.04 | 5 | Mission Center Road, Auto Circle | |||
3.90 | 6A | Texas Street, Qualcomm Way | |||
4.38 | 6B | I-805 (Jacob Dekema Freeway) – Los Angeles, National City, Chula Vista | |||
5.64 | 7 | I-15 (Escondido Freeway) – Riverside, San Diego | Signed as exits 7A (north) and 7B (south) eastbound, 7A (south) and 7B (north) westbound | ||
6.27 | 8 | Mission Gorge Road, Fairmount Avenue | Eastbound exit is part of exit 7 | ||
7.06 | 9 | Waring Road | |||
8.34 | 10 | College Avenue | Serves San Diego State University | ||
La Mesa | 9.59 | 11 | Lake Murray Boulevard, 70th Street | ||
10.57 | 12 | Fletcher Parkway, Baltimore Drive | |||
10.97 | 13A | Spring Street – Downtown La Mesa | No westbound exit | ||
11.10 | 13A | El Cajon Boulevard | Westbound exit and eastbound entrance; former I-8 Bus. west | ||
11.76 | 13B | Jackson Drive, Grossmont Boulevard | No eastbound entrance | ||
12.12 | 14B | La Mesa Boulevard, Grossmont Center Drive | Signed as exit 14B weastbound | ||
12.34 | 14A | SR 125 to SR 94 | Signed as exit 14A eastbound | ||
12.65 | 14C | Severin Drive, Fuerte Drive | |||
El Cajon | 13.66 | 15 | El Cajon Boulevard (I-8 Bus. east) | Eastbound exit and westbound entrance | |
14.59 | 16 | Main Street | |||
15.30 | 17A | Johnson Avenue | Eastbound exit and westbound entrance | ||
15.80 | 17 | SR 67 north / Magnolia Avenue – Santee, Lakeside, Ramona | Signed as exits 17B (SR 67) and 17C (Magnolia Avenue) eastbound | ||
16.47 | 18 | Mollison Avenue | |||
17.36 | 19 | 2nd Street | Former SR 54 west | ||
17.83 | 20A | East Main Street (I-8 Bus. west) | Westbound exit and eastbound entrance | ||
R18.73 | 20B | Greenfield Drive – Crest | Signed as exit 20 eastbound | ||
R20.04 | 22 | Los Coches Road – Lakeside | |||
R21.82 | 23 | Lake Jennings Park Road | |||
R25.69 | 27 | Dunbar Lane – Harbison Canyon | |||
R28.46 | 30 | Tavern Road (I-8 Bus. east) – Alpine | |||
R31.34 | 33 | Willows Road, Alpine Boulevard (I-8 Bus. west) – Alpine | |||
R34.33 | 36 | East Willows Road | |||
R37.83 | 40 | SR 79 north (Japatul Road) – Julian | |||
R43.53 | 45 | Pine Valley, Julian | |||
R44.93 | 47 | Sunrise Highway (CR S1) | |||
R48.84 | 51 | Buckman Springs Road | |||
R51.98 | 54 | Kitchen Creek Road – Cameron Station | |||
R61.15 | 61 | Crestwood Road – Live Oak Springs | |||
R65.90 | 65 | SR 94 west – Campo, Boulevard | |||
R73.95 | 73 | Jacumba | |||
R77.58 | 77 | In-Ko-Pah Park Road | |||
Imperial IMP R0.00-R96.99 |
R3.09 | 80 | Mountain Springs Road | ||
R10.01 | 87 | SR 98 east – Calexico | Eastbound exit and westbound entrance | ||
Ocotillo | R11.92 | 89 | Imperial Highway (CR S2) – Ocotillo | ||
R23.48 | 101 | Dunaway Road | |||
R29.93 | 107 | Drew Road (CR S29) – Seeley | |||
R33.99 | 111 | Forrester Road (CR S30) | |||
El Centro | R36.97 | 114 | Imperial Avenue (I-8 Bus. east) – El Centro | ||
R37.97 | 115 | SR 86 (4th Street, I-8 Bus. west) – El Centro | |||
R38.96 | 116 | Dogwood Road (CR S31) | |||
R40.94 | 118 | SR 111 – Brawley, Indio, Calexico | Signed as exits 118A (south) and 118B (north) | ||
R42.54 | 120 | Bowker Road | |||
R47.78 | 125 | SR 7 south / Orchard Road (CR S32) | |||
R50.49 | 128 | Bonds Corner Road | Former SR 115 | ||
R53.50 | 131 | SR 115 (Van Der Linden Road) – Holtville | Former US 80 | ||
R65.75 | 143 | SR 98 west – Calexico | |||
R68.83 | 146 | Brock Research Center Road | |||
R73.48 | 151 | Gordons Well | |||
80.80 | 156 | Grays Well Road | |||
R83.82 | 159 | Ogilby Road (CR S34) | |||
Felicity | R88.70 | 164 | Sidewinder Road | ||
R90.74 | 166 | SR 186 south (Algodones Road) – Andrade | |||
R94.98 | 170 | Winterhaven Drive (CR S24, I-8 Bus. east) – Winterhaven | |||
R96.55 | 172 | Winterhaven Drive, Fourth Avenue (I-8 Bus. west) – Winterhaven | |||
R96.99 | Arizona state line | ||||
1.000 mi = 1.609 km; 1.000 km = 0.621 mi Concurrency terminus • Closed/Former • Incomplete access • Unopened |
County | Location | Mile[10] | # | Destinations | Notes |
---|---|---|---|---|---|
Yuma | Yuma | 0.59 | 1 | Redondo Center Drive, Giss Parkway | |
2.23 | 2 | US 95 (16th Street) – San Luis, Quartzsite, Yuma Proving Grounds | |||
3.98 | 3 | SR 280 south (Avenue 3E) – Yuma International Airport, Marine Corps Air Station Yuma, Yuma County Fairgrounds | |||
7.66 | 7 | Araby Road – Arizona Western College | |||
9.44 | 9 | I-8 Bus. (Avenue 8½E) | |||
12.27 | 12 | Fortuna Road | |||
14.28 | 14 | Foothills Boulevard | |||
21.06 | 21 | Dome Valley | |||
30.84 | 30 | Avenue 29E – Wellton | |||
37.99 | 37 | Avenue 36E – Roll | |||
42.10 | 42 | Avenue 40E – Tacna | |||
54.98 | 54 | Avenue 52E – Mohawk Valley | |||
67.49 | 67 | Dateland | |||
73.53 | 73 | Aztec | |||
78.51 | 78 | Spot Road | |||
Maricopa | 87.10 | 87 | Sentinel, Hyder, Auga Caliente | ||
102.34 | 102 | Painted Rock Road | |||
106.56 | 106 | Paloma Road | |||
111.49 | 111 | Citrus Valley Road | |||
Gila Bend | 115.68 | 116 | I-8 Bus. east / SR 85 – Phoenix, Ajo | ||
119.47 | 119 | I-8 Bus. west (Butterfield Trail) to SR 85 north / I-10 | |||
140.86 | 140 | Freeman Road | |||
144.60 | 144 | Vekol Valley Road | |||
Pinal | 151.73 | 151 | SR 84 east to SR 347 north – Maricopa | ||
161.61 | 161 | Stanfield | |||
167.61 | 167 | Montgomery Road | |||
169.72 | 169 | Bianco Road | |||
172.62 | 172 | Thornton Road – Casa Grande | |||
174.62 | 174 | Trekell Road – Casa Grande | |||
Casa Grande | 178.36 | 178 | I-10 – Phoenix, Tucson | Eastbound exit and westbound entrance; signed as exits 178A (west) and 178B (east) |
Interstate 8 Business | |
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Location: | El Centro, California |
Business Loop Interstate 8 is a business loop route that diverges from Interstate 8 in El Centro, California to pass through the downtown area. Business Interstate 8 originates and terminates with I-8 and acts as a direct link to El Centro as I-8 bypasses the downtown area.
Business Interstate 8's path through El Centro traces roughly three sides of a rectangle with I-8 constituting the fourth side. Bus-8 begins at its western terminus with I-8 by going north along Imperial Avenue. When Bus-8 reaches the intersection of Adams Avenue it turns east along that road. Along this stretch Bus-8 is joined by State Route 86 which approaches from the north along Imperial Ave, and by Imperial County Route S80 which approaches from the west along Adams Ave. The three routes continue joined as Adams Ave ends and turns south along Fourth Ave where S80 then turns to continue east. Bus-8 and SR 86 continue south running concurrent until Bus-8 reaches its eastern terminus with I-8.
The Imperial Ave section of Bus-8 is city maintained by El Centro, the rest of Bus-8 is state maintained due to its concurrency with SR 86.
Along its concurrency with SR 86, Bus-8 is part of the Juan Bautista De Anza National Historic Trail.
Main Interstate Highways (major interstates highlighted) |
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4 | 5 | 8 | 10 | 12 | 15 | 16 | 17 | 19 | 20 | 22 | 24 | 25 | 26 | 27 | 29 | 30 | |||
35 | 37 | 39 | 40 | 43 | 44 | 45 | 49 | 55 | 57 | 59 | 64 | 65 | 66 | 68 | 69 | ||||
70 | 71 | 72 | 73 | 74 | 75 | 76 (W) | 76 (E) | 77 | 78 | 79 | 80 | 81 | 82 | ||||||
83 | 84 (W) | 84 (E) | 85 | 86 (W) | 86 (E) | 87 | 88 (W) | 88 (E) | 89 | 90 | |||||||||
91 | 93 | 94 | 95 | 96 | 97 | 99 | H-1 | H-2 | H-3 | ||||||||||
Unsigned | A-1 | A-2 | A-3 | A-4 | PRI-1 | PRI-2 | PRI-3 | ||||||||||||
Lists | Primary | Main - Intrastate - Suffixed - Temporary - Future - Gaps | |||||||||||||||||
Auxiliary | Main - Future - Unsigned | ||||||||||||||||||
Other | Standards - Business - Bypassed - Tolled |
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