Editing Interstate 8 (section)

===San Diego to Arizona border===
The entirety of Interstate 8 in California is defined in the California Streets and Highways Code as '''Route 8''', whose definition in section 308 is as follows<ref>[https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=SHC&sectionNum=308. California Code, SHC 308.]</ref>:<blockquote>Route 8 is from:<br>(a) Sunset Cliffs Boulevard to [[Interstate 5 in California|Route 5]] in San Diego<br>(b) Route 5 in San Diego to Yuma via El Centro.</blockquote>
The freeway begins at the intersection of Sunset Cliffs Boulevard and Nimitz Boulevard in [[San Diego]]. For its first few miles, it parallels the [[San Diego River]] floodway. Near [[Old Town, San Diego|Old Town San Diego]], I-8 intersects with I-5 as well as with Rosecrans Street, the former routing of [[California State Route 209|SR&nbsp;209]].<ref name="tgsd2">{{cite map |author = Thomas Brothers |location = Irvine, CA |publisher = Thomas Brothers |title = San Diego County Road Atlas |year = 1998 |page = 1232 |isbn = 0-88130-902-8 |oclc = 38909538 |scale = 1:316,800 }}</ref> Even though the freeway west of I-5 is signed with interstate shields, it is not considered a chargeable interstate highway according to Federal Highway Administration route logs, which defines I-8's western terminus at I-5.<ref>{{cite web | url=https://www.fhwa.dot.gov/planning/national_highway_system/interstate_highway_system/routefinder/table01.cfm | title=Table 1 - Main Routes - FHWA Route Log and Finder List - Interstate Highway System - National Highway System - Planning - FHWA }}</ref> Under regular circumstances, the [[California Department of Transportation]] (Caltrans) would sign this freeway segment as State Route 8.

As the freeway enters [[Mission Valley, San Diego|Mission Valley]], it continues eastward, bisecting the area known as "Hotel Circle" that has several hotels.  I-8 then has interchanges with [[California State Route 163|SR&nbsp;163]], [[Interstate 805|I-805]], and [[Interstate 15 in California|I-15]]. In [[La Mesa, California|La Mesa]], the route intersects [[California State Route 125|SR&nbsp;125]], and in [[El Cajon, California|El Cajon]]  it intersects with [[California State Route 67|SR&nbsp;67]]. From Mission Valley through El Cajon, it is paralleled by the [[San Diego Trolley]] [[Green Line (San Diego Trolley)|Green Line]].

East of El Cajon, it ascends into the mountains and the [[Cleveland National Forest]], traveling through towns such as [[Alpine, California|Alpine]] then going by the [[Viejas Casino]] before reaching [[Pine Valley, California|Pine Valley]]. This route achieves four 4,000-foot (1219.2 meters) high points at [[Carpenter Summit]], then crosses the [[Pine Valley Creek Bridge]] before the [[Laguna Summit]], followed by the [[Crestwood Summit]], then the [[Tecate Divide]],<ref name="acme" /> After the Laguna Summit, the road passes a [[United States Border Patrol interior checkpoints|U.S. border patrol interior checkpoint]] that was constructed in 1995 near Buckman Springs Road turnoff just east of the summit.<ref>{{Cite news |title = Border Patrol Will Open Checkpoint on I-8 |last = Sanchez, Leonel |date = October 19, 1995 |work = San Diego Union-Tribune |page = A1 |oclc = 25257675 }}</ref> However, this resulted in smugglers driving the wrong way on I-8 at high speeds in order to avoid the checkpoint, causing several crashes, even after concrete barriers were installed.<ref>{{Cite news |title = State Asked for Barriers to Stop I-8 Cross-overs |last = Vigil, Jennifer |date = September 21, 2003 |work = San Diego Union-Tribune |page = B1 |oclc = 25257675 }}</ref><ref>{{Cite news |title = Smugglers Make East County Highways Deadly |date = October 13, 2005 |work = San Diego Union-Tribune |page = B13 |oclc = 25257675 }}</ref> The freeway intersects with [[California State Route 79|SR&nbsp;79]] in the national forest before passing through the [[La Posta Indian Reservation|La Posta]] and [[Campo Indian Reservation|Campo]] Indian reservations.

In [[Boulevard, California|Boulevard]], I-8 has an interchange with the eastern end of [[California State Route 94|SR&nbsp;94]].<ref name="tgsd">{{cite map |author = Thomas Brothers |location = Irvine, CA |publisher = Thomas Brothers |title = San Diego County Road Atlas |year = 2009 |pages = 429–430, 1232–1237, 1251–1252, 1268–1270, 1298–1300 |isbn = 978-1-58174-110-0 |oclc = 263420904 }}</ref><ref name="rmcn">{{cite map |author = Rand McNally |title = The Road Atlas: United States, Canada, and Mexico |year = 2008 |location = Chicago |publisher = Rand McNally |page = 15 |isbn = 978-0-528-93961-7 |oclc = 173493291 |scale = c. 1:1.584,000 }}<br />{{cite map |author = Rand McNally |title = The Road Atlas: United States, Canada, and Mexico |year = 2008 |location = Chicago |publisher = Rand McNally |page = 17 |isbn = 978-0-528-93961-7 |oclc = 173493291 |scale = c. 1:190,080 |inset = San Diego }}</ref>

I-8 straddles the [[San Diego County, California|San Diego]]–[[Imperial County, California|Imperial]] county line for a few miles before turning east. At the Mountain Springs/In-Ko-Pah grade, the freeway is routed down two separate canyons—[[Devils Canyon (Jacumba Mountains)|Devils Canyon]] for westbound traffic and [[In-Ko-Pah Gorge]] for eastbound traffic—as it descends {{convert|3000|ft|m|abbr=on}} in {{convert|11|mi|km|abbr=on}}.<ref name="acme">{{cite map |url = http://mapper.acme.com/?ll=32.69646,-116.08944&z=13&t=T&marker0=41.19886%2C-120.94414 |title = Acme Mapper |publisher = Acme Maps |access-date = April 28, 2013 |author = OpenStreetMap |archive-url = https://web.archive.org/web/20140714165023/http://mapper.acme.com/?ll=32.69646,-116.08944&z=13&t=T&marker0=41.19886%2C-120.94414 |archive-date = July 14, 2014 |url-status = live }}</ref> In places, the median is over {{convert|1.5|mi|km|abbr=on}} wide.<ref name="rmcn"/><ref name="tg">{{cite map |author = Thomas Brothers |location = Irvine, CA |publisher = Thomas Brothers |title = California Road Atlas and Driver's Guide |year = 2000 |pages = 107, 111, 112, 212, 213, 214, V |oclc = 41359350 }}</ref> This portion of the road is known for high winds through the canyons that have made driving difficult, sometimes resulting in closure of the freeway;<ref name="grade"/> in 1966, the [[California Highway Patrol]] estimated that winds blew at speeds of up to {{convert|100|mph|km/h|abbr=on}}.<ref>{{cite news |title = Screen To Curb Devilish Wind |work = The San Diego Union |date = March 8, 1966 |author = Hudson, Ken |page = A17 |oclc = 13155544 }}</ref> The route enters the Imperial Valley, where it intersects with SR&nbsp;98, a highway leading to [[Calexico, California|Calexico]], and passes near the [[Desert View Tower]]. I-8 then goes through [[Ocotillo, California|Ocotillo]] and [[Coyote Wells, California|Coyote Wells]] before entering the city of [[El Centro, California|El Centro]] several miles later.<ref name="rmcn"/><ref name="tg"/>

In El Centro, I-8 intersects with [[California State Route 86|SR&nbsp;86]] and [[California State Route 111|SR&nbsp;111]], both north–south routes which connect to [[Interstate 10 in California|I-10]] in the [[Coachella Valley]], north of the [[Salton Sea]]. [[California State Route 115|SR&nbsp;115]] and SR&nbsp;98 end at I-8 east of El Centro. The route also has the lowest above-ground elevation of any Interstate at {{convert|52|ft|m|abbr=on}} [[below sea level]] near El Centro.<ref name="fhwaoldfact">{{cite web |url = https://highways.dot.gov/highway-history/interstate-system/50th-anniversary |title = Previous Interstate Facts of the Day |publisher = Federal Highway Administration |work = Celebrating the Eisenhower Interstate Highway System |date = February 29, 2012 |access-date = September 29, 2012 |author = Federal Highway Administration |archive-url = https://web.archive.org/web/20060426084506/http://www.fhwa.dot.gov/interstate/previousfacts.cfm |archive-date = April 26, 2006 |url-status = live }}</ref> The freeway then traverses the [[Imperial Sand Dunes Recreation Area]] and intersects with [[California State Route 186|SR&nbsp;186]] leading south to [[Baja California Norte]], Mexico.<ref name="rmcn"/><ref name="tg"/> I-8 runs parallel to the [[All-American Canal]] across the desert for roughly {{convert|55|mi|km|abbr=on}}.<ref>{{harvp|Pittman|1995|p=341}}.</ref> At points in eastern Imperial County, the [[Mexico–United States border|Mexican border]] is less than {{convert|0.5|mi|km|abbr=on}} south of the Interstate. I-8 then passes through [[Felicity, California|Felicity]] and [[Winterhaven, California|Winterhaven]] before crossing the [[Colorado River]] on a bridge into [[Yuma, Arizona]].<ref name="rmcn"/><ref name="tg"/>

I-8 is part of the [[California Freeway and Expressway System]]<ref name="cafes">{{CAFESystem}}</ref> and is eligible for the [[State Scenic Highway System (California)|State Scenic Highway System]] from [[Interstate 5 in California|I-5]] to the western junction of SR&nbsp;98,<ref name="scenic">{{CA scenic}}</ref> though it is not an official state scenic highway.<ref name="actualscenic">{{Caltrans scenic|access-date=December 14, 2016}}</ref> It is officially known as the Border Friendship Route from San Diego to the Arizona state line. The Interstate is signed as the Ocean Beach Freeway west of I-5. For the entire length within San Diego County and into Imperial County, it is signed as the Kumeyaay Highway, after [[Kumeyaay people|the local Native American tribe]] and their traditional trade route which the Interstate follows.<ref>{{CA Named Freeways |pages=15, 289}}</ref><ref>{{Cite book |first1 = Geralyn Marie |last1 = Hoffman |first2 = Lynn H. |last2 = Gamble |author3 = San Diego State University Institute for Regional Studies of the Californias |year = 2006 |url = https://books.google.com/books?id=rfg4TOb4o10C&pg=PA24 |title = A Teacher's Guide to Historical and Contemporary Kumeyaay Culture |location = San Diego |publisher = San Diego State University Institute for Regional Studies of the Californias |page = 24 |isbn = 978-0-925613-51-6 |oclc = 173480703 |access-date = October 10, 2016 |archive-url = https://web.archive.org/web/20161130215433/https://books.google.com/books?id=rfg4TOb4o10C&pg=PA24 |archive-date = November 30, 2016 |url-status = live }}</ref> Between Old Town and El Cajon, I-8 is called the Mission Valley Freeway.<ref name="tg"/> In 2014, I-8 had an [[annual average daily traffic]] (AADT) of 11,800&nbsp;vehicles between Bonds Corner Road and SR&nbsp;115, as well as between SR&nbsp;98 and Imperial Highway, and 239,000&nbsp;vehicles between I-805 and I-15, the latter of which was the highest AADT for the highway in California.<ref name=traffic>{{Caltrans traffic|year=2014|start=7|end=10|access-date=December 14, 2016}}</ref>

{{anchor|Arizona}}