Editing Interstate Highway System (section)

===Construction===
[[File:National Highway Program - National System of Interstate Highways - Rural Status of Improvement, 1965.png|thumb|1955 map: The planned status of US Highways in 1965, as a result of the developing Interstate Highway System]]
[[File:STEEL RODS, MADE FROM SHREDDED AUTOS, ARE BEING USED FOR REINFORCEMENT IN THIS SECTION OF I-55, NORTH OF DURANT. IT... - NARA - 546265.jpg|thumb|upright=0.677|[[Interstate 55 in Mississippi|I‑55]] under construction in [[Mississippi]] in May 1972]]
[[File:CA 58 I5 FHWA 1957 5776 14.jpg|thumb|right|1957 aerial photograph showing a recently constructed interchange on I-5 in [[Glendale, California]]]]
Some sections of highways that became part of the Interstate Highway System actually began construction earlier.

Three states have claimed the title of first Interstate Highway. Missouri claims that the first three contracts under the new program were signed in Missouri on August 2, 1956. The first contract signed was for upgrading a section of [[U.S. Route 66|US Route 66]] to what is now designated [[Interstate 44]].<ref name="weingroff">{{cite magazine |url = https://highways.dot.gov/public-roads/summer-1996/three-states-claim-first-interstate-highway |title = Three States Claim First Interstate Highway |last = Weingroff |first = Richard F. |date = Summer 1996 |volume = 60 |issue = 1 |magazine = Public Roads |access-date = February 16, 2008 |issn = 0033-3735 |archive-url = https://web.archive.org/web/20101011155643/http://www.fhwa.dot.gov/publications/publicroads/96summer/p96su18.cfm |archive-date = October 11, 2010 |url-status = live }}</ref> On August 13, 1956, work began on [[US Route 40|US 40]] (now I-70) in St. Charles County.<ref name=Sherrill>{{cite news |url = https://www.journalnow.com/news/local/facts-and-history-of-north-carolina-interstates/article_cf1a0399-801f-57f5-a0a0-ab4ec56851d5.html |title = Facts and History of North Carolina Interstates |last = Sherrill |first = Cassandra |work = [[Winston-Salem Journal]] |date = September 28, 2019 |access-date = September 29, 2019 |archive-date = September 29, 2019 |archive-url = https://web.archive.org/web/20190929193542/https://www.journalnow.com/news/local/facts-and-history-of-north-carolina-interstates/article_cf1a0399-801f-57f5-a0a0-ab4ec56851d5.html |url-status = live }}</ref><ref name="weingroff"/>

Kansas claims that it was the first to start paving after the act was signed. Preliminary construction had taken place before the act was signed, and paving started September 26, 1956. The state marked its portion of [[Interstate 70|I-70]] as the first project in the United States completed under the provisions of the new Federal-Aid Highway Act of 1956.<ref name="weingroff" />

The [[Pennsylvania Turnpike]] could also be considered one of the first Interstate Highways, and is nicknamed "Grandfather of the Interstate System".<ref name=Sherrill/> On October 1, 1940, {{convert|162|mi|km|0}} of the highway now designated I‑70 and I‑76 opened between [[Irwin, Pennsylvania|Irwin]] and [[Carlisle, Pennsylvania|Carlisle]]. The [[Pennsylvania|Commonwealth of Pennsylvania]] refers to the turnpike as the Granddaddy of the Pikes, a reference to [[Toll road|turnpike]]s.<ref name="weingroff" />

Milestones in the construction of the Interstate Highway System include:
* October 17, 1974: [[Nebraska]] becomes the first state to complete all of its mainline Interstate Highways with the dedication of its final piece of [[Interstate 80 in Nebraska|I-80]].<ref>{{cite web |url = http://www.nebraskatransportation.org/i-80-anniv/index.htm |title = I-80 50th Anniversary Page |author = Nebraska Department of Roads |date = n.d. |publisher = Nebraska Department of Roads |access-date = August 23, 2009 |archive-url = https://web.archive.org/web/20131221052401/http://www.transportation.nebraska.gov/i-80-anniv/index.htm |archive-date = December 21, 2013 |url-status = live |author-link = Nebraska Department of Roads }}</ref>
* October 12, 1979: The final section of the Canada to Mexico freeway [[Interstate 5]] is dedicated near [[Stockton, California]]. Representatives of the two neighboring nations attended the dedication to commemorate the first contiguous freeway connecting the North American countries.<ref>{{cite web |url = http://www.dot.ca.gov/interstate/timeline.htm |author = California Department of Transportation |date = n.d. |publisher = California Department of Transportation |title = Timeline of Notable Events of the Interstate Highway System in California |access-date = March 2, 2014 |archive-url = https://web.archive.org/web/20140306100816/http://www.dot.ca.gov/interstate/timeline.htm |archive-date = March 6, 2014 |url-status = dead |author-link = California Department of Transportation }}</ref>
* August 22, 1986: The final section of the coast-to-coast [[Interstate 80|I-80]] ([[San Francisco, California]], to [[Teaneck, New Jersey]]) is dedicated on the western edge of [[Salt Lake City, Utah]], making I-80 the world's first contiguous freeway to span from the Atlantic to Pacific Ocean and, at the time, the longest contiguous freeway in the world. The section spanned from [[Utah State Route 68|Redwood Road]] to just west of the [[Salt Lake City International Airport]]. At the dedication it was noted that coincidentally this was only {{convert|50|mi|km}} from [[Promontory Summit]], where a similar feat was accomplished nearly 120&nbsp;years prior, the driving of the [[golden spike]] of the United States' [[First transcontinental railroad]].<ref name="highway history">{{cite magazine |url = https://www.fhwa.dot.gov/infrastructure/30thannv.cfm |title = America Celebrates 30th Anniversary of the Interstate System |magazine = US Highways |date = Fall 1986 |access-date = March 10, 2012 |archive-url = https://web.archive.org/web/20111024114212/https://www.fhwa.dot.gov/infrastructure/30thannv.cfm |archive-date = October 24, 2011 |url-status = live }}</ref><ref name="nytimes">{{cite news |url = https://www.nytimes.com/1986/08/25/us/around-the-nation-transcontinental-road-completed-in-utah.html |title = Around the Nation: Transcontinental Road Completed in Utah |work = [[The New York Times]] |date = August 25, 1986 |access-date = February 9, 2017 |archive-url = https://web.archive.org/web/20170316115134/http://www.nytimes.com/1986/08/25/us/around-the-nation-transcontinental-road-completed-in-utah.html |archive-date = March 16, 2017 |url-status = live }}</ref><ref name="utahmap">{{cite map |author = Utah Transportation Commission |year = 1983 |title = Official Highway Map |scale = Scale not given |location = Salt Lake City |publisher = [[Utah Department of Transportation]] |inset = Salt Lake City }}</ref>
* August 10, 1990: The final section of coast-to-coast [[Interstate 10|I-10]] ([[Santa Monica, California]], to [[Jacksonville, Florida]]) is dedicated, the [[Papago Freeway Tunnel]] under downtown [[Phoenix, Arizona]]. Completion of this section was delayed due to a [[highway revolt|freeway revolt]] that forced the cancellation of an originally planned elevated routing.<ref name="pr">{{cite magazine |url = https://highways.dot.gov/public-roads/januaryfebruary-2006/year-interstate |title = The Year of the Interstate |last = Weingroff |first = Richard F. |magazine = Public Roads |date = January 2006 |volume = 69 |issue = 4 |issn = 0033-3735 |access-date = March 10, 2012 |archive-url = https://web.archive.org/web/20120104024139/http://www.fhwa.dot.gov/publications/publicroads/06jan/01.cfm |archive-date = January 4, 2012 |url-status = live }}</ref>
* September 12, 1991: [[Interstate 90|I-90]] becomes the final coast-to-coast Interstate Highway ([[Seattle, Washington]] to [[Boston, Massachusetts]]) to be completed with the dedication of an elevated [[viaduct]] bypassing [[Wallace, Idaho]], which opened a week earlier.<ref>{{cite news |last=Devlin |first=Sherry |date=September 8, 1991 |title=No Stopping Now |page=E1 |work=The Missoulian |url=https://www.newspapers.com/clip/90334418/no-stopping-now/ |via=Newspapers.com |accessdate=September 12, 2023 |archive-date=December 10, 2021 |archive-url=https://web.archive.org/web/20211210064843/https://www.newspapers.com/clip/90334418/no-stopping-now/ |url-status=live }}</ref><ref>{{cite news |last=Free |first=Cathy |date=September 15, 1991 |title=Engineer pleased with his Wallace freeway 'work of art' |page=B3 |work=The Spokesman-Review |url=https://www.newspapers.com/clip/89735440/engineer-pleased-with-his-wallace/ |via=Newspapers.com |accessdate=September 12, 2023 |archive-date=October 9, 2022 |archive-url=https://web.archive.org/web/20221009233910/https://www.newspapers.com/clip/89735440/engineer-pleased-with-his-wallace/ |url-status=live }}</ref> This section was delayed after residents forced the cancellation of the originally planned at-grade alignment that would have demolished much of [[Wallace Historic District|downtown Wallace]]. The residents accomplished this feat by arranging for most of the downtown area to be declared a [[historic districts in the United States|historic district]] and listed on the [[National Register of Historic Places]]; this succeeded in blocking the path of the original alignment. Two days after the dedication residents held a mock funeral celebrating the removal of the last stoplight on a transcontinental Interstate Highway.<ref name="pr" /><ref>{{cite web |url = http://www.itd.idaho.gov/50.years/I-50_I-90.html |author = Idaho Transportation Department |publisher = Idaho Transportation Department |title = Celebrating 50 years of Idaho's Interstates |date = May 31, 2006 |access-date = March 10, 2012 |url-status = dead |archive-url = https://web.archive.org/web/20120224045451/http://itd.idaho.gov/50.Years/I-50_I-90.html |archive-date = February 24, 2012 |author-link = Idaho Transportation Department }}</ref>
* October 14, 1992: The original Interstate Highway System is proclaimed to be complete with the opening of [[Interstate 70 in Colorado|I-70]] through [[Glenwood Canyon]] in [[Colorado]]. This section is considered an engineering marvel with a {{convert|12|mi|km|adj=on}} span featuring 40&nbsp;bridges and numerous tunnels and is one of the most expensive rural highways per mile built in the United States.<ref name="funfacts">{{cite web |author = Colorado Department of Transportation |date = n.d. |url = http://www.dot.state.co.us/50anniversary/funfacts.cfm |title = CDOT Fun Facts |access-date = February 15, 2008 |publisher = Colorado Department of Transportation |url-status = dead |archive-url = https://web.archive.org/web/20080116125059/http://www.dot.state.co.us/50anniversary/funfacts.cfm |archive-date = January 16, 2008 |author-link = Colorado Department of Transportation }}</ref><ref name="12yearslater">{{cite web |url = http://www.tfhrc.gov/pubrds/04mar/04.htm |title = Glenwood Canyon 12 Years Later |first1 = Karen |last1 = Stufflebeam Row |first2 = Eva |last2 = LaDow |first3 = Steve |last3 = Moler |name-list-style = amp |date = March 2004 |publisher = Federal Highway Administration |access-date = May 11, 2008 |archive-url = https://web.archive.org/web/20130117094404/http://www.fhwa.dot.gov/publications/publicroads/04mar/ |archive-date = January 17, 2013 |url-status = dead }}</ref>

The initial cost estimate for the system was $25&nbsp;billion over 12&nbsp;years; it ended up costing $114&nbsp;billion (equivalent to $425&nbsp;billion in 2006<ref name="usatoday062206">{{cite news |work = [[USA Today]] |last = Neuharth |first = Al |date = June 22, 2006 |title = Traveling Interstates is our Sixth Freedom |url = https://www.usatoday.com/news/opinion/columnist/neuharth/2006-06-22-interstates_x.htm |access-date = May 9, 2012 |archive-url = https://web.archive.org/web/20120819092803/http://www.usatoday.com/news/opinion/columnist/neuharth/2006-06-22-interstates_x.htm |archive-date = August 19, 2012 |url-status = live }}</ref> or ${{formatprice|{{inflation|US-GDP|425000000000|2006}}}} in {{inflation-year|US-GDP}}{{inflation-fn|US-GDP}}) and took 35&nbsp;years.<ref name="mndot50">{{cite web |author = Minnesota Department of Transportation |url = http://www.dot.state.mn.us/interstate50/50facts.html |title = Mn/DOT Celebrates Interstate Highway System's 50th Anniversary |year = 2006 |access-date = January 17, 2008 |publisher = Minnesota Department of Transportation |archive-url = https://web.archive.org/web/20071204072603/http://www.dot.state.mn.us/interstate50/50facts.html <!-- Bot retrieved archive --> |archive-date = December 4, 2007 |author-link = Minnesota Department of Transportation }}</ref>