Interstate 405 (California)

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Interstate 405 marker

Interstate 405
San Diego Freeway
I-405 highlighted in red
Route information
Defined by Streets and Highways Code § 615
Maintained by Caltrans
Length72.415 mi[1] (116.541 km)
Major junctions
South end I-5 in Irvine
North end I-5 near San Fernando
CountiesOrange, Los Angeles
Highway system
US 395US 466

Interstate 405 (usually pronounced four-oh-five), also known as I-405 or colloquially as "the 405"[2], is a major north–south Interstate Highway in Southern California. It is a bypass auxiliary route of Interstate 5 (similar to I-215 bypassing I-15 in the Inland Empire), running along the southern and western parts of the Greater Los Angeles Area from Irvine in the south to near San Fernando in the north. The entire route is known as the northern segment of the San Diego Freeway. It goes past Los Angeles International Airport (LAX).

I-405 is a heavily traveled thoroughfare by both commuters and by freight haulers along its entire length and is the busiest and most congested freeway in the United States.[3][4] The freeway's annual average daily traffic between exits 21 and 22 in Seal Beach reached 374,000 in 2008, making it the highest count in the nation.[5] It has played a crucial role in the development of dozens of cities and suburbs along its route through Los Angeles and Orange counties.

Route description[edit]

I-405 in the Sepulveda Pass

Interstate 405 begins at the El Toro Y interchange with Interstate 5 in southeastern Irvine. It then runs northwest through Orange County to Long Beach in Los Angeles County. The freeway then roughly follows the outline of the Pacific coast, varying between five and ten miles (16 km) inland before crossing over the Sepulveda Pass in the Santa Monica Mountains. I-405 next travels northerly through the San Fernando Valley, before its termination with I-5 in the Mission Hills district of Los Angeles. Large portions of the route closely parallel Sepulveda Boulevard.

The San Diego Freeway, near the interchange with the Ventura Freeway (U.S. Route 101)

The freeway's congestion problems are legendary, leading to jokes that the road was numbered 405 because traffic moves at "four or five" miles per hour, or because drivers need "four or five" hours to get anywhere. Indeed, average speeds as low as 5 mph are routinely recorded during morning and afternoon commutes, and its interchanges with the Ventura Freeway (U.S. Route 101) and with the Santa Monica Freeway (Interstate 10) each consistently rank among the five most congested freeway interchanges in the United States. As a result of these congestion problems, it may take longer to pass through the entire Los Angeles area using this bypass route instead of merely taking the primary route I-5 through Downtown.

Of the major reasons for the excessively heavy traffic on the freeway, the 405 is the only major North–South freeway in the densely populated areas between West LA and Downtown, crossing the Santa Monica Mountains and connecting San Fernando Valley and the Los Angeles basin. Another parallel freeway is proposed to connect the Valley and the LA basin (the Laurel Canyon Freeway or La Cienega Freeway), but has faced upper class home-owner opposition.[6] Despite 4 years of construction disruptions, billions of dollars of public money, LA Times commentary claims traffic with the lane expansions is actually just as bad or worse.[7]

I-405 is part of the California Freeway and Expressway System,[8] and is part of the National Highway System,[9] a network of highways that are considered essential to the country's economy, defense, and mobility by the Federal Highway Administration.[10] The freeway from present-day I-10 to I-5 near San Fernando is known as the San Diego Freeway, and less commonly as the Sepulveda Freeway (after Sepulveda Boulevard).[11]

Points of interest[edit]

The Bristol exit near South Coast Plaza and Segerstrom Center for the Arts, with Saddleback in the background

There are a number of points of interest that I-405 passes by or connects to. For transportation, these include (in the order passed from south to north) John Wayne Airport in Orange County, Long Beach Municipal Airport and Los Angeles International Airport. With connections, it is also very close to the Port of Long Beach, the Port of Los Angeles and Burbank Airport.

Some of the educational institutions it passes include the California state universities at Dominguez Hills, Long Beach, and Northridge; the University of California at Irvine and UCLA, Loyola Marymount University, and Pepperdine University's West LA and Irvine campuses.

I-405 also passes cultural facilities such as the Getty Center, the Skirball Cultural Center and the Segerstrom Center for the Arts. In addition, several shopping malls such as Sherman Oaks Galleria, Westfield Culver City, The Promenade at Howard Hughes Center, Westminster Mall, South Coast Plaza and the Irvine Spectrum Center are located along I-405.

The route also passes by or through many recreation and commercial destinations. These include more than ten California state beaches, several other beaches owned by counties and municipalities, many of the beach cities favored by tourists, as well as Century City and Marina del Rey.

The view from the Getty Center, south of the Sepulveda Pass, looking east, south, and west. The San Diego Freeway can be seen at the center


California 7.svg
1955 map of the planned Interstates in the Los Angeles area. Present-day I-405 roughly corresponds to the 1955 proposed route through the western regions of the area.
Civil engineers Marilyn Reece & Carol Schumaker, at the Reece-designed I-10/I-405 interchange, 1964

I-405 was approved as a chargeable interstate (in other words, an interstate financed with federal funds) in 1955. Construction began in 1957 with the first section, mostly north of LAX Airport being completed in 1961 (signed as SR 7) followed by sections west of Interstate 605 within the following few years. The highway was renumbered to Interstate 405 during the 1964 renumbering. The final section covering most of Orange County opened in 1969. Construction required the already existing Mulholland Highway to be re-routed 1.1 miles to the south along a new 579-foot-long bridge, the Mulholland Drive Bridge, to span Interstate 405.[12]


A section of I-405 was closed over the weekend of Friday, July 15, 2011 as part of the Sepulveda Pass Improvements Project.[13] Before the closing, local radio DJs and television newscasts referred to it as "Carmageddon" and "Carpocalypse", parodying the notion of Armageddon and the Apocalypse, since it was anticipated that the closure would severely impact traffic.[14][15]

In reality, traffic was lighter than normal across a wide area. California Department of Transportation reported that fewer vehicles used the roads than usual, and those who did travel by road arrived more quickly than on a normal weekend.[16] The Metrolink commuter train system recorded its highest-ever weekend ridership since it began operating in 1991. Ridership was 50% higher than the same weekend in 2010, and 10% higher than the previous weekend ridership record, which occurred during the U2 360° Tour in June 2011.[17] In response to jetBlue Airlines' offer of special flights between Bob Hope Airport in Burbank and Long Beach Airport, a distance of only 29 mi (47 km), for $4,[18][19] a group of cyclists did the same journey in one and a half hours, compared to two and a half hours by plane (including a drive to the airport from West Hollywood 90 minutes in advance of the flight and travel time to the end destination).[20] There was also some debate about whether the Los Angeles area could benefit from car-free weekends regularly.[16]

The Los Angeles County Metropolitan Transportation Authority had full closure of a 10-mile stretch of I-405 on the weekend of September 29–30, 2012, while construction crews worked to demolish a portion of the Mulholland Bridge.[21]

Researchers at the University of California, Los Angeles used the closure of I-405 to study particulate matter air pollution. The researchers took air samples before, during, and after the closure. The researchers found an 83% reduction in ultrafine particles, 55% reduction in fine particle matter, and 62% less black carbon.[22]

Sepulveda Pass Improvements Project[edit]

The $1 billion Sepulveda Pass Improvements Project added a high-occupancy vehicle lane and associated changes to freeway entrances, exits, and underpasses along a 10-mile stretch through the Sepulveda Pass between I-10 and U.S. 101/Ventura Boulevard.[23] The project was completed as a design-build in contrast to the traditional design-bid-build used typically in infrastructure improvement. This section of I-405 was closed for a weekend in mid-July 2011 to demolish the Mulholland Drive Bridge, and a 10-mile section was closed for the last weekend of September 2012 (See 'Carmageddon 2011' and 'Carmageddon 2012' above).[13]

Jamzilla was the name for the I-405 closure on President's Day Weekend 2014. There were lane closures and complete closures on I-405 starting February 14 at 10 p.m. until February 18 at 6 a.m. to pave and re-stripe the northbound lanes.[24]

On May 23, 2014, the 10-mile high-occupancy vehicle lane was opened to traffic.[25]


Manchester and Century Boulevard interchanges[edit]

Proposed changes between the Manchester and Century Boulevard interchanges in the City of Inglewood to provide a new southbound on-ramp and a new northbound off-ramp for Arbor Vitae Street, to reconstruct and widened the Arbor Vitae Street over-bridge and replace the Century Boulevard overcrossing structure.[26] This work would reduce congestion on the approach to Los Angeles International Airport.[citation needed] The California Department of Transportation has not yet issued a start date for this work.

Orange County[edit]

The Orange County Transportation Authority is currently preparing the design plans to add a HOT express lane and one mixed flow lane in each direction between Highway 73 in Costa Mesa and I-605 in Seal Beach.[27] The I-405 Improvement Project is starting construction in 2018 and is scheduled to be completed in 2023.


UCLA protest 1966[edit]

Following the 1966 UCLA–USC rivalry game, USC was voted into the Rose Bowl despite the UCLA team's having defeated the Trojans—with both teams having only one loss during the season. UCLA students protested by blocking the freeway's northbound lanes at Wilshire Boulevard.[citation needed]

The O.J. Simpson chase 1994[edit]

While dangerous high-speed chases along the San Diego Freeway are not uncommon, perhaps the most famous chase in its history was also one of the slowest. On the afternoon of June 17, 1994, former football star O.J. Simpson, who was accused of murdering his ex-wife Nicole Brown Simpson and waiter Ronald Goldman, took to the freeway in a white Ford Bronco (driven by former USC teammate Al Cowlings) with police in pursuit. A bizarre, widely televised low-speed chase ensued and ended hours later when Simpson returned to his Brentwood estate via the Sunset Boulevard exit and surrendered to law enforcement.[28]

Murder of Ennis Cosby 1997[edit]

Ennis Cosby, the only son of Bill Cosby, was murdered along I-405 in Los Angeles on January 16, 1997, while fixing a flat tire.[29]

In popular culture[edit]

I-405 was the location for the short film 405.

The Swedish rock band Europe's song "California 405" is featured on their 2015 studio album War of Kings.

Chuck Lorre used an end-of-show vanity card in 2013 to berate workers on the 405 for their apparent lack of progress after five years.[30]

The Death Cab For Cutie song "405" on their second studio album, We Have the Facts and We're Voting Yes, may be incorrectly associated with California's I-405. The song is actually referring to I-405 in Seattle, as the band is from Bellingham.[31]

The song "Drive" on Halsey's 2015 album Badlands uses the story of a reckless drive on the I-405 to frame its relatively unstructured lyrics.[32]

Exit list[edit]

Except where prefixed with a letter, postmiles were measured on the road as it was in 1964, based on the alignment that existed at the time, and do not necessarily reflect current mileage. R reflects a realignment in the route since then, M indicates a second realignment, L refers an overlap due to a correction or change, and T indicates postmiles classified as temporary (for a full list of prefixes, see the list of postmile definitions).[1] Segments that remain unconstructed or have been relinquished to local control may be omitted. The numbers reset at county lines; the start and end postmiles in each county are given in the county column.

ORA 0.23–24.18
Irvine0.23 I-5 south (San Diego Freeway) – San DiegoSouthbound exit and northbound entrance; former US 101 south; southern terminus; I-5 north exit 94A
I-5 southHOV access only; southbound exit and northbound entrance
1ALake Forest DriveSouthbound exit and northbound entrance
1BBake ParkwaySouthbound exit and northbound entrance
0.951CIrvine Center DriveSigned as exit 1 northbound
1.802 SR 133 (Laguna Freeway) – Laguna BeachNo northbound exit to SR 133 north; SR 133 north exit 8, south exits 8A-B
2.883Shady Canyon Drive / Sand Canyon Avenue
3.954Jeffrey Road / University Drive
5.625Culver Drive
6.927Jamboree Road
7.808 MacArthur Boulevard – John Wayne Airport
Costa Mesa8.749A SR 55 (Costa Mesa Freeway)SR 55 north exit 6, south exits 6A-B
SR 55 northHOV access only
9BAnton Boulevard / Avenue of the ArtsNorthbound exit and entrance
9.519BBristol Street
10.2810 SR 73 south (Corona del Mar Freeway) to SR 55 south (Costa Mesa Freeway) – San Diego via toll roadSouthbound exit and northbound entrance
11South Coast DriveNorthbound exit only
10.7511AFairview RoadSigned as exit 11 northbound
11.4511BHarbor Boulevard – Costa MesaSigned as exit 11 northbound
Fountain Valley12.4712Euclid Street / Newhope Street / Ellis Avenue
13.7814Brookhurst Street – Fountain Valley
14.8215AWarner Avenue eastSouthbound exit and northbound entrance
Huntington Beach15.2115BMagnolia Street / Warner Avenue westSigned as exit 15 northbound
16.5416 SR 39 (Beach Boulevard) – Westminster, Huntington Beach
Westminster17.7518Bolsa Avenue / Goldenwest StreetGoldenwest Street is signed as Golden West Street.
19.1619Westminster Avenue / Springdale Street
20Bolsa Chica Road / Valley View StreetFor southbound only, omits Valley View Street on signage
SR 22 eastHOV access only; southbound exit and northbound entrance
20.7521 SR 22 east (Garden Grove Freeway) / Valley View Street / Bolsa Chica Road / Garden Grove Boulevard – Garden GroveSouthern end of SR 22 concurrency, signage omits Bolsa Chica Road.
Seal Beach22.6422Seal Beach Boulevard / Los Alamitos BoulevardFormer SR 35
23.2823 SR 22 west (7th Street) – Long BeachNorthern end of SR 22 concurrency; I-605 exit 1A
I-605 northHOV access only; northbound exit and southbound entrance
24.0424A I-605 north (San Gabriel River Freeway)Signed as exit 24 northbound; I-605 south exits 1B-1C; SR 22 east exit 2
Los Angeles
LA 0.27–48.64
Long Beach0.4524BStudebaker RoadSouthbound exit and northbound entrance
1.1125Palo Verde Avenue
1.6426AWoodruff AvenueNo southbound exit
2.1826BBellflower BoulevardSigned as exit 26 southbound
3.3227 SR 19 (Lakewood Boulevard) – Long Beach Airport
4.8829Spring Street / Cherry Avenue – Signal HillSigned as exits 29A (south) and 29B (north)
Signal Hill5.3929COrange Avenue
Long Beach6.0830AAtlantic Avenue
6.3430BLong Beach BoulevardFormer SR 15
6.7032APacific AvenueSouthbound exit and northbound entrance
7.6032 I-710 (Long Beach Freeway) – Long Beach, PasadenaSigned as exits 32A (north) and 32B (south) northbound, and 32B (south) and 32C (north) southbound; I-710 exit 4
8.0632CHughes Way / Santa Fe AvenueSigned as exit 32D southbound
Carson8.7833AAlameda Street (SR 47 south)
9.5633BWilmington Avenue
10.5434Carson Street
11.2235Avalon Boulevard – CarsonNorthbound exit to Avalon Boulevard south is via exit 34.
12.6036Main StreetNorthbound exit and southbound entrance
12.9737A I-110 (Harbor Freeway) – San Pedro, Los AngelesSigned as exit 37 northbound; former US 6; I-110 exit 9
Los Angeles13.2837BVermont AvenueSouthbound exit and northbound entrance
13.8338ANormandie Avenue – Gardena
14.4038BWestern Avenue
Torrance15.4539Crenshaw Boulevard – Torrance
16.5740 To SR 91 / Artesia BoulevardSigned as exit 40A southbound; former SR 91
16.8840BRedondo Beach Boulevard – Redondo BeachSouthbound exit and northbound entrance
Lawndale17.5942A SR 107 (Hawthorne Boulevard) – Lawndale
Redondo Beach18.2342BInglewood Avenue
Hawthorne19.2143Rosecrans Avenue – Manhattan BeachSigned as exits 43A (east) and 43B (west) southbound
20.2244El Segundo Boulevard – El Segundo
Los AngelesR21.1845A I-105 (Century Freeway) – El Segundo, NorwalkSigned as exit 45 southbound; serves Los Angeles International Airport; I-105 east exit 2, west exit 2B
R21.2245BImperial HighwaySouthbound exit is part of exit 46.
Inglewood22.2246 Century Boulevard – LAX Airport
23.3647Manchester Boulevard / La Cienega Boulevard / Florence AvenueManchester Boulevard was former SR 42.
Los Angeles24.2748La Tijera Boulevard
24.5649AHoward Hughes Parkway / Sepulveda BoulevardSigned as exit 49 southbound
Culver City25.4649BSepulveda Boulevard / Slauson Avenue (SR 90 east)Northbound exit only; SR 90 exit 2
25.9550AJefferson BoulevardSigned as exit 50B northbound
25.9550B SR 90 (Marina Freeway) / Slauson Avenue – Marina del ReySigned as exit 50A northbound; no access from I-405 north to SR 90 east; SR 90 exit 2
27.2051Culver Boulevard / Washington Boulevard – Culver City
27.9652Venice Boulevard (SR 187) / Washington Boulevard
Los Angeles29.1653ANational BoulevardNorthbound exit and southbound entrance
29.5453B I-10 (Santa Monica Freeway) – Santa Monica, Los AngelesSigned as exit 53 southbound; I-10 exits 3A-B
30.1854Olympic Boulevard / Pico BoulevardSouthbound exit and northbound entrance; former SR 26
30.8655A SR 2 (Santa Monica Boulevard)Former US 66
31.5455BWilshire BoulevardSigned as exits 55B (east) and 55C (west) southbound
32.5056Montana AvenueNorthbound exit only; demolished[36]
33.0057ASunset BoulevardSigned as exit 57 southbound
33.2957BMoraga DriveNorthbound exit and entrance
34.7659Getty Center Drive
36.0361Mulholland Drive / Skirball Center Drive
39.0063AVentura Boulevard / Sepulveda Boulevard / Valley Vista Boulevard
39.4363B US 101 (Ventura Freeway) – Ventura, Los AngelesUS 101 exit 19A
40.2964Burbank Boulevard
41.3665Victory Boulevard – Van Nuys
42.3666Sherman Way – Van Nuys AirportSigned as exits 66A (east) and 66B (west) northbound
43.7668Roscoe Boulevard – Panorama City
44.7469Nordhoff Street
46.2470Devonshire Street – Granada Hills
46.8571A SR 118 (Ronald Reagan Freeway) – Simi ValleySigned as exit 71 southbound; no southbound exit to SR 118 east or northbound entrance from SR 118 west; SR 118 east exit 42A, west exit 42B
47.2471BSan Fernando Mission Boulevard – San FernandoNorthbound exit and southbound entrance
47.7572Rinaldi Street – Mission Hills
48.64 I-5 north (Golden State Freeway) – Bakersfield, SacramentoNorthbound exit and southbound entrance; northern terminus; I-5 south exit 158
1.000 mi = 1.609 km; 1.000 km = 0.621 mi

See also[edit]


  1. ^ a b c California Department of Transportation. "State Truck Route List". Sacramento: California Department of Transportation. Archived from the original (XLS file) on June 30, 2015. Retrieved June 30, 2015.
  2. ^ Masters, Nathan. "The 5, the 101, the 405: Why Southern Californians Love Saying 'the' Before Freeway Numbers".
  3. ^ Time For Kids | Classroom | Home | U.S. Highways With the Most Traffic Archived August 11, 2011, at the Wayback Machine.
  4. ^ Santa Monica College Corsair News Article Archived August 15, 2007, at the Wayback Machine.
  5. ^ "Most Travelled Urban Highways Average Annual Daily Traffic". 2010-07-27. Retrieved 2013-01-26.
  6. ^ "Crossroads of Confusion". Los Angeles Times. March 20, 1998. p. 2. Retrieved October 11, 2012.
  7. ^
  8. ^ California State Legislature. "Section 250–257". Streets and Highways Code. Sacramento: California State Legislature. Retrieved June 9, 2017.
  9. ^ Federal Highway Administration (March 25, 2015). National Highway System: Los Angeles, CA (PDF) (Map). Scale not given. Washington, DC: Federal Highway Administration. Retrieved July 29, 2017.
  10. ^ Natzke, Stefan; Neathery, Mike & Adderly, Kevin (June 20, 2012). "What is the National Highway System?". National Highway System. Washington, DC: Federal Highway Administration. Retrieved July 1, 2012.
  11. ^ California Department of Transportation; California State Transportation Agency (January 2015). 2014 Named Freeways, Highways, Structures and Other Appurtenances in California. Sacramento: California Department of Transportation. pp. 82, 266. Archived from the original (PDF) on May 30, 2015. Retrieved May 30, 2015.
  12. ^ Racine, Ned (January 11, 2011). "How the Mulholland Drive bridge was constructed". Los Angeles County Metropolitan Transportation Authority. Retrieved July 16, 2011.
  13. ^ a b "Interstate 405: The 'Carmageddon', History, Myth and Trivia". During 53 hours of closure, the north side of the Mulholland Bridge will be demolished as part of the $1 billion Sepulveda Pass Improvements Project.
  14. ^ Judy Gish Issue Date: 06/2011. "Inside Seven – Caltrans, District 7 – Monthly Newsletter". Retrieved 2013-01-26.
  15. ^ Gostar, Reza (2011-06-09). "Carpocalypse: The Weekend the 405 Freeway Will Stand Still – Brentwood, California Patch". Retrieved 2013-01-26.
  16. ^ a b Mather, Kate; Bloomekatz, Ari; Saillant, Saillant (July 19, 2011). "In 'Carmageddon,' some see road map for the future". Los Angeles Times. Retrieved August 1, 2011.
  17. ^ "Metrolink sets weekend ridership recording during 405 closure". The Source. Retrieved July 21, 2011.
  18. ^ "JetBlue — 405 Freeway Closure? We're So Over It!". JetBlue. Retrieved 2013-01-26.
  19. ^ "Great Circle Mapper". Retrieved 2013-01-26.
  20. ^ "LA avoids feared 'Carmageddon' traffic jam". The Independent. July 17, 2011. Retrieved July 17, 2011.
  21. ^ Morgan, Jared (July 19, 2012). "Carmageddon 2012 Announced, Full 405 Closure in September". Retrieved September 4, 2012.
  22. ^ Winer, Arthur; Zhu, Yifang; Paulson, Suzanne (Spring 2014). "Carmageddon or Carmaheaven? Air Quality Results of a Freeway Closure" (PDF). Access. 44: 17–21.
  23. ^ "Sepulveda Pass Improvement Project". Los Angeles County Metropolitan Transportation Authority. Retrieved July 15, 2011.
  24. ^ Groves, Martha (February 14, 2014). "Jamzilla lane closures on the 405 Freeway begin tonight". Los Angeles Times. Retrieved October 4, 2014.
  25. ^ "Carpool lane on North 405 Freeway opens". KABC-TV Los Angeles. May 23, 2014. Retrieved May 23, 2014.
  26. ^ "405 on the move-PR" (PDF).
  27. ^ "OCTA approves study of 405 widening project". Daily Pilot. February 10, 2010. Retrieved July 16, 2011.
  28. ^ THE SIMPSON CASE: THE INMATE; Simpson, Under Suicide Watch, Is Jailed on 2 Murder Charges, Seth Mydans, The New York Times, June 19, 1994, Retrieved December 9, 2007
  29. ^ Bill Cosby's Son Is Slain Along Freeway, B. Drummond Ayres Jr., The New York Times, January 17, 1997, Retrieved December 9, 2007
  30. ^ "CLP – Vanity Card #429". Retrieved October 4, 2014.
  31. ^ As told in track nine of their iTunes Originals Album
  32. ^ Sherman, Maria (August 21, 2015). "Halsey Shares Unrestrained New 'Badlands' Song, "Drive"". Fuse. Retrieved 2017-12-17.
  33. ^ California Department of Transportation (July 2007). "Log of Bridges on State Highways". Sacramento: California Department of Transportation.
  34. ^ California Department of Transportation, All Traffic Volumes on CSHS, 2005 and 2006
  35. ^ California Department of Transportation, California Numbered Exit Uniform System, I-405 Northbound and I-405 Southbound, accessed February 2008
  36. ^ "405 Freeway NB Montana Avenue Offramp Dies At 57". CBS. Los Angeles, California: CBS Radio Inc. November 24, 2013. Retrieved March 19, 2014.

External links[edit]

Route map:

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