Interstate 15 in California
|Defined by S&HC § 315|
|Maintained by Caltrans|
|Length:||287.26 mi (462.30 km)|
|Existed:||1957 – present|
|South end:||I-8 / SR 15 in San Diego|
| I-215 in Murrieta
SR 91 in Corona
I-10 in Ontario
SR 210 in Rancho Cucamonga
I-215 in San Bernardino
SR 58 / I-40 in Barstow
|North end:||I-15 at Nevada state line|
In the U.S. state of California, Interstate 15 (I-15) is a major north–south route through the San Bernardino, Riverside, and San Diego Counties, and it has a length of 287.26 miles (462.30 km) in the state. It is a major thoroughfare for traffic between Southern California and Las Vegas, Nevada, as well as points beyond. It is also the main route for traffic between San Diego and the Inland Empire.
Interstate 15 has portions designated as the Escondido Freeway, Avocado Highway, Temecula Valley Freeway, Ontario Freeway, Barstow Freeway, CHP Officer Larry L. Wetterling and San Bernardino County Sheriff’s Lieutenant Alfred E. Stewart Memorial Highway, or Mojave Freeway.
Route description 
Interstate 15 is part of the California Freeway and Expressway System, and it is eligible for designation as a state highway within the State Scenic Highway System; however the state transportation authority, Caltrans, has not done so. There are various local names for the highway, such as the Escondido Freeway between San Diego and Escondido. I-15 between SR 163 and Pomerado Road/Miramar Road is known as the Semper Fi Highway in recognition of the nearby Marine Corps Air Station Miramar. North of the Escondido city limits it is known as the Avocado Highway, whose designation ends upon entering Temecula. There are other local names as noted below.
Heading northward, I-15 currently begins at Interstate 8, at the same place that its continuation, State Route 15, begins its southward journey. I-15 goes through Mission Valley and intersects with State Route 52, before merging with State Route 163. After traversing the Marine Corps Air Station Miramar, I-15 comes into Rancho Peñasquitos, where it intersects with the end of State Route 56. Northward, the route crosses Lake Hodges inside the upper San Diego city limits. I-15 continues north into Escondido, where it interchanges with State Route 78. There are high-occupancy toll lanes in the center of I-15 from State Route 163 to State Route 78.
North of Escondido, I-15 goes through hilly terrain and farmland, descending to the town of Fallbrook and intersecting State Route 76 (SR 76), before it crosses the county line into Riverside County and descends to the Inland Empire. In Riverside County, SR 79 runs concurrently with I-15 for a four-mile (6 km) portion in Temecula, before it splits away running north to Hemet. Then, I-15 intersects with the southern end of Interstate 215, which continues the designation of the Escondido Freeway. Interstate 15 continues north as the Temecula Valley Freeway.
In Murrieta, I-15 splits from its first and only spur route in California, Interstate 215, which runs through the two largest cities in the Inland Empire, San Bernardino and Riverside. I-15 runs along the eastern edge of the Santa Ana Mountains, passing the town of Lake Elsinore. It continues through the suburban areas in the western Inland Empire, passing Corona and Ontario, California. The highway is then rejoined by I-215, before heading northwards and upward through the Cajon Pass, an important mountain pass that is the primary route between Southern California and points eastwards and northeastwards.
The portion of I-15 that is located between its northern and southern junctions with I-215 is also used by many local residents as the major north–south route for the western portions of the San Bernardino-Riverside-Ontario metropolitan area. (I-215 serves a similar function in the eastern portion of the metropolitan area. These two highways are the only continuous north–south freeways in the area.)
North of Limonite Avenue (south of SR 60), I-15 is known as the Ontario Freeway. I-15 intersects State Route 60, Interstate 10, and State Route 210 in rapid succession as it goes through Mira Loma, Ontario, and Rancho Cucamonga. As it nears Devore, I-15 merges with Interstate 215, where it is called the Barstow Freeway or the Mojave Freeway. A short section between SR 138 and Oak Hill Road is also designated as the CHP Officer Larry L. Wetterling and San Bernardino County Sheriff’s Lieutenant Alfred E. Stewart Memorial Highway.
North of the Cajon Pass, I-15 traverses the Mojave Desert towns of Hesperia and Victorville. I-15 passes through desert for 30 miles (48 km) before reaching Barstow, then continues past Zzyzx Road, before reaching the town of Baker. The sign for Zzyzx Road — alphabetically the last place name in the world — is a landmark of sorts on the drive between Los Angeles and Las Vegas. I-15 enters Nevada near the casino town of Primm, formerly known as Stateline, Nevada.
I-15 continues thereafter to Las Vegas, Salt Lake City, and on into Idaho and Montana, before ending at the Canadian border, where Alberta Highway 4 continues the ribbon of asphalt into Canada. Because it joins with the western end of I-70 in Southwestern Utah, I-15 also forms part of a major east–west corridor connecting Southern California with Denver, St. Louis, and points east.
The Mojave Freeway is fairly busy on weekdays, since it connects the rapidly growing exurbs of the Victor Valley with the Los Angeles area. On weekends and holidays, however, it can sometimes be jammed with Californians driving to Las Vegas for short vacations.
Construction is currently underway to rehabilitate the pavement on I-15 and to add truck lanes to separate autos from truck traffic.
I-15 was initially planned to run from I-10 in San Bernardino along the current I-215 alignment then up through the Cajon Pass and on to Las Vegas, with a distance of 186.24 miles (299.72 km) within the state. California successfully argued the addition south to San Diego, suggesting that the freeway would connect the major military bases former March AFB and former NAS (now MCAS) Miramar. US 395 was then signed TEMP-15 and the "old" I-15 between Devore and San Bernardino became I-215.
On January 24, 1957, the State Highway Commission defined the Escondido Freeway as what are now Routes 15 and 215 from Route 805 to Route 91. This entire segment was previously U.S. Route-395 when it was named. Since then, the definition was extended on Route 15 south to Route 8 by Assembly Concurrent Resolution 34, Chapter 67 in 1979. Meanwhile, the segment of Route 15 from the San Diego County Line to the I-15/I-215 interchange was named the Temecula Valley Freeway in 1990.
This legal definition has been amended twice: First in 1990, the California Assembly passed Concurrent Resolution 125, Chapter 78, renaming I-15 between the San Diego County Line (which is further south from Interstate 215) and Bundy Canyon Road near Lake Elsinore as the Temecula Valley Freeway.
Then in 1993, the California Assembly passed legislation officially designating State Route 71 as a part of the Chino Valley Freeway. However, the name "Corona Freeway" is, confusingly, sometimes still applied to this portion of State Route 71; despite the change, guide signs on
eastbound and SR 57 southbound at the Kellogg Interchange in Pomona still refer to SR 71 as the "Corona Freeway".
State Route 31 
In 1933, Interstate 15 was defined as Legislative Route 193, running from pre-1964 Legislative Route 43 (present State Route 91) in Corona to pre-1964 Legislative Route 9 (now State Route 66, and was extended north to pre-1964 Legislative Route 31 (present I-15 and I-215) in 1935. The piece south of U.S. Route 60 (Mission Boulevard), running along North Main Street, Hamner Avenue and Milliken Avenue, was state-maintained by 1955, but was not assigned a signed number. This was still the only existing piece in 1963, and had a planned freeway replacement to the east.
In the 1964 renumbering, the route was assigned as State Route 31. It was added to the Interstate Highway System in February 1972 as a realignment of Interstate 15 (the former alignment became Interstate 15E). Legislative changes were made in 1974, eliminating SR 31 (along with State Route 71 south of Corona) in favor of I-15. However, SR 31 continued to be signed — as temporary Interstate 15 - until present I-15 was finished. (A 1986 map shows state maintenance continuing north past SR 60 to Jurupa Street, where it turned east to I-15.)
Most of Interstate 15 is undergoing major improvements from Devore to the Nevada State Line, beginning in 2002 and costing $349 million. This project will improve traffic flow on the heavily traveled highway for those going to and from Las Vegas. Most of the construction was completed by winter 2009. Projects include adding truck lanes on hills (39 miles or 63 kilometres at various locations), repaving 76 miles (122 km) of I-15 at various locations, adding exit numbers, renovating and rehabilitating the rest area between Baker and the Nevada State Line (Valley Wells Rest Area), reconstructing bridges in Baker, and moving the agriculture inspection station from Yermo to the Nevada State Line and including a truck weigh station.
As of March 2008, construction is underway to add a northbound truck descending lane and to repave lanes between Bailey Road and Yates Well Road.
Exit list 
||San Diego||6.13||9.87||6|| I-8 Beaches, El Centro
SR 15 south (Escondido Freeway)
|Freeway continues beyond I-8 as I-15|
|6.82||10.98||7||Friars Road – Qualcomm Stadium||Signed as exits 7A (east) and 7B (west) northbound|
|9.24||14.87||9||Balboa Avenue, Tierrasanta Boulevard||Former SR 274 west|
|10.00||16.09||10||Clairemont Mesa Boulevard||Southbound exit is part of exit 11|
|12.12||19.51||12||SR 163 south (Cabrillo Freeway)||Northbound exit is via exit 11; former US 395 south|
|13.33||21.45||13||Miramar Way||Serves Marine Corps Air Station Miramar|
|14.29||23.00||14||Miramar Road, Pomerado Road|
|15.00||24.14||15||Carroll Canyon Road|
|15.92||25.62||16||Mira Mesa Boulevard|
|17.31||27.86||17||Mercy Road, Scripps Poway Parkway|
|18.18||29.26||18||CR S4 (Poway Road) / Rancho Peñasquitos Boulevard|
|19.47||31.33||19||SR 56 west (Ted Williams Freeway) / Ted Williams Parkway|
|20.57||33.10||21||Carmel Mountain Road|
|21.92||35.28||22||Camino del Norte|
|22.94||36.92||23||Bernardo Center Drive|
|23.69||38.13||24||Rancho Bernardo Road|
|26.03||41.89||26||CR S5 (Pomerado Road) / West Bernardo Drive|
|Escondido||26.97||43.40||27||Via Rancho Parkway|
|28||Centre City Parkway (I-15 Bus. north)||Northbound exit and southbound entrance; former US 395 north|
|30.09||48.43||30||9th Avenue, Auto Park Way|
|30.63||49.29||31||Valley Parkway – Downtown Escondido|
|31.52||50.73||32||SR 78 – Oceanside, Ramona|
|32.86||52.88||33||El Norte Parkway|
|33.92||54.59||34||Centre City Parkway (I-15 Bus. south)||Southbound exit and northbound entrance; former US 395 south|
|36.64||58.97||37||CR S12 (Deer Springs Road) / Mountain Meadow Road|
|40.84||65.73||41||Gopher Canyon Road, Old Castle Road|
|43.28||69.65||43||Old Highway 395||Former US 395|
|46.49||74.82||46||SR 76 – Pala, Oceanside|
|50.59||81.42||51||CR S13 (Mission Road) – Fallbrook|
|54.07||87.02||54||Rainbow Valley Boulevard|
||Temecula||57.70||92.86||58||SR 79 south – Temecula, Indio||South end of SR 79 overlap, former SR 71 south|
|59.24||95.34||59||Rancho California Road, Old Town Front Street|
|60.88||97.98||61||SR 79 north (Winchester Road) – Hemet||North end of SR 79 overlap|
|Murrieta||63.00||101.39||63||I-215 north (Escondido Freeway) – Riverside, San Bernardino||Southbound exit is via exit 64; former I-15E north / US 395 north|
|63.73||102.56||64||Murrieta Hot Springs Road|
|64.85||104.37||65||California Oaks Road|
|67.90||109.27||68||Clinton Keith Road|
|70.56||113.56||71||Bundy Canyon Road|
|Lake Elsinore||73.42||118.16||73||Diamond Drive, Railroad Canyon Road|
|75.21||121.04||75||Main Street (I-15 Bus. north)|
|76.54||123.18||77||SR 74 (Central Avenue) – San Juan Capistrano, Perris|
|80.95||130.28||81||Lake Street (I-15 Bus. south)|
|84.66||136.25||85||Indian Truck Trail|
|87.65||141.06||88||Temescal Canyon Road||Former SR 71|
|89.90||144.68||90||Weirick Road, Dos Lagos Drive|
|92.08||148.19||92||El Cerrito Road|
|Corona||92.95||149.59||93||Ontario Avenue||Former SR 71|
|95.76||154.11||96||SR 91 (Riverside Freeway) – Riverside, Beach Cities||Signed as exits 96A (east) and 96B (west) southbound; former US 91|
|Norco||97.14||156.33||97||Hidden Valley Parkway|
|97.90||157.55||98||Second Street (I-15 Bus. north)|
|99.86||160.71||100||Sixth Street (I-15 Bus. south)|
|102||Schleisman Road||Proposed interchange|
|105||Cantu-Galleano Ranch Road|
|105.73||170.16||106||SR 60 (Pomona Freeway) – Los Angeles, Riverside||Signed as exits 106A (east) and 106B (west) northbound|
||Ontario||107.55||173.08||108||Jurupa Street||Former SR 31 south|
|108.93||175.31||109||I-10 (San Bernardino Freeway, I-10 Bus.) – Los Angeles, San Bernardino, Indio||Signed as exits 109A (west) and 109B (east) southbound; former US 99|
|Rancho Cucamonga||109.59||176.37||110||4th Street|
|111.85||180.01||112||SR 66 (Foothill Boulevard)||Former US 66|
|115||SR 210 – Pasadena, San Bernardino, Redlands||Signed as exits 115A (east) and 115B (west) northbound and exits 115A (west) and 115B (east) southbound|
|117||Duncan Canyon Road||Proposed interchange|
|San Bernardino||122.19||196.65||122||Glen Helen Parkway|
|122.91||197.80||123||I-215 south (Barstow Freeway) – San Bernardino, Riverside||Left exit southbound; former I-15E south / US 66 west / US 91 south / US 395 south|
|124.09||199.70||124||Kenwood Avenue||Former US 66 east|
|129.14||207.83||129||Cleghorn Road||Former US 66 west|
|130.50||210.02||131||SR 138 – Palmdale, Silverwood Lake|
|137.75||221.69||138||Oak Hill Road|
|140||Ranchero Road||Proposed interchange|
|141.45||227.64||141||US 395 north – Bishop, Adelanto||Northbound exit and southbound entrance|
|Joshua Street to US 395 north||Southbound exit and northbound entrance|
|Hesperia||143.13||230.35||143||Main Street – Hesperia, Phelan|
|Victorville||146.72||236.12||147||Bear Valley Road – Lucerne Valley|
|148||La Mesa Road, Nisqualli Road||Proposed interchange|
|149.64||240.82||150||SR 18 west (Palmdale Road, I-15 Bus. north)||South end of SR 18 overlap; former US 66 east / US 91 north|
|150.56||242.30||151A||Roy Rogers Drive|
|152.62||245.62||153A||SR 18 east (D Street, I-15 Bus. south) – Victorville, Apple Valley||North end of SR 18 overlap; former US 66 / US 91|
|153.53||247.08||154||Stoddard Wells Road|
|156.64||252.09||157||Stoddard Wells Road – Bell Mountain|
|160.96||259.04||161||Dale Evans Parkway – Apple Valley|
|164.82||265.25||165||Wild Wash Road|
|Barstow||174.97||281.59||175||Outlet Center Drive|
|179.46||288.81||179||SR 58 west – Bakersfield|
|180.78||290.94||181||L Street, West Main Street (I-15 Bus. north)|
|182.67||293.98||183||SR 247 south (Barstow Road)|
|183.55||295.40||184A||I-40 east (Needles Freeway) – Needles||Southbound exit is via exit 184|
|184.08||296.25||184B||East Main Street (I-15 Bus. south)||Signed as exit 184 southbound; former US 66|
|186.01||299.35||186||Old Highway 58||Former SR 58 west / US 91 south / US 466 west|
|188.72||303.72||189||Fort Irwin Road||Serves Fort Irwin|
|190.96||307.32||191||Ghost Town Road||Serves the ghost town of Calico|
|Yermo||193.77||311.84||194||Calico Road – Yermo|
|195.51||314.64||196||Yermo Road – Yermo|
|Agricultural Inspection Station (southbound only)|
|216.53||348.47||Clyde V. Kane Rest Area|
|Zzyzx||239.31||385.13||239||Zzyzx Road – Zzyzx|
|Baker||244.95||394.21||245||Baker Boulevard (I-15 Bus. north) – Baker||Northbound exit and southbound entrance; former US 91 north / US 466 east|
|245.70||395.42||246||SR 127 north / Kelbaker Road – Death Valley|
|247.59||398.46||248||Baker Boulevard (I-15 Bus. south) – Baker||Southbound exit and northbound entrance; former US 91 south / US 466 west|
|Halloran Springs||258.74||416.40||259||Halloran Springs Road|
|264.70||425.99||265||Halloran Summit Road|
|270.29||434.99||Valley Wells Rest Area|
|290.53||467.56||291||Yates Well Road|
|295.37||475.35||Nevada state line|
- Staf (October 31, 2002). "Table 1: Main Routes of the Dwight D. Eisenhower National System Of Interstate and Defense Highways as of October 31, 2002". Route Long and Finder List. Federal Highway Administration. Retrieved November 29, 2011.
- California Assembly. "Section 250–257". Streets and Highways Code. Legislative Counsel of California. Retrieved November 29, 2011.
- California Assembly. "Section 260–284". Streets and Highways Code. Legislative Counsel of California. Retrieved November 29, 2011.
- Cadd, Dennis (July 11, 2012). "Officially Designated Scenic Highways". California Department of Transportation. Retrieved July 18, 20012.
- Faigin, Daniel P. (July 18, 2012). "Routes 9 through 16". California Highways. Self-published. Retrieved July 18, 2012.[unreliable source?]
- "Interstate 15 Express Lanes". Sandag.org. Retrieved March 31, 2012.
- Thomas Brothers (2000). California Road Atlas and Driver's Guide (Map). p. V, 99, 106.
- "ACR-127 CHP Officer Larry L. Wetterling and San Bernardino County Sheriff’s Lieutenant Alfred E. Stewart Memorial Highway". California Legislative Information. Retrieved 22 May 2013.
- The highway was featured on the television program Dangerous Drives (Speed), which illustrated the difficulties of patrolling the highway due to excessive speed and congestion. The 45-minute episode "Dangerous Drives - Highway Patrol" originally aired in January 2010.
- Caltrans, p. 60
- Caltrans, p. 63
- Caltrans, p. 69
- Caltrans, p. 67
- Faigin, Daniel P. (July 18, 2012). "Routes 193 through 200". California Highways. Self-published. Retrieved July 18, 2012.[unreliable source?]
- H.M. Gousha. 1955 Gousha Los Angeles district map (Map). http://members.cox.net/mkpl2/hist/map-ca1955-la.jpg. Retrieved November 29, 2011.[dead link]
- 1963 Caltrans Los Angeles and vicinity map (Map). http://www.cahighways.org/maps/1963routes.jpg. Retrieved November 29, 2011.
- Faigin, Daniel P. (July 18, 2012). "Interstate Highway Types and the History of California's Interstates". California Highways. Self-published. Retrieved July 18, 2012.[unreliable source?]
- Faigin, Daniel P. (July 18, 2012). "Routes 25 through 32". California Highways. Self-published. Retrieved July 18, 2012.[unreliable source?]
- 1986 Caltrans Los Angeles and vicinity map (Map). http://www.cahighways.org/maps/1986map.jpg. Retrieved November 29, 2011.
- California Department of Transportation (June 2004) (PDF). Interstate 15 Major Improvements from Barstow to Nevada stateline (Map). Archived from http://www.dot.ca.gov/dist8/projects/15/I-15%20Brstw%20-STLN.revsd%206-2004%20copy.pdf the original on September 11, 2008. http://web.archive.org/web/20080911032558/http://www.dot.ca.gov/dist8/projects/15/I-15%20Brstw%20-STLN.revsd%206-2004%20copy.pdf.
- Warring, KS (January 14, 2007). "Interstate 15 Freeway Interchanges" (PDF). California Numbered Exit Uniform System. California Department of Transportation. Retrieved 2009-02-05.
- Bender, Mary (July 20, 2005). "Country road to get new course: Schleisman, Plans are under way to widen the artery in the high-growth area, and link it to I-15". Riverside, CA. Retrieved July 18, 2012.
- Edwards, Andrew (July 6, 2012). "Nearly $14 million to fund Fontana interchange paves way for development". Inland Valley Daily Bulletin. Retrieved July 18, 2012.
- "Ranchero Road Interchange Moves Forward". High Desert Business Journal (Apple Valley, CA). May 7, 2012. Retrieved July 18, 2012.
- "Interstate 15: La Mesa & Nisqualli Road Interchange, Victorville". High Desert Business Journal (Apple Valley, CA). July 9, 2012. Retrieved July 18, 2012.
- Works cited
- Caltrans (January 2009). 2008 Named Freeways, Highways, Structures and Other Appurtenances in California (PDF). California Department of Transportation. Retrieved November 29, 2011.
|Wikimedia Commons has media related to: Interstate 15 in California|
- Interstate 15 @ Interstate-Guide.com
- California @ AARoads.com – Interstate 15
- Caltrans: Interstate 15 highway conditions
- California Highways: Interstate 15