Editing Interstate Highway System (section)

==History==

===Planning===
{{listen |filename=Cadillacsquareexcerpt.ogg |title=Remarks in Cadillac Square, Detroit |description=President Eisenhower delivered remarks about the need for a new highway program at [[Cadillac Square]] in Detroit on October 29, 1954<br />[https://www.fhwa.dot.gov/interstate/audiotext.cfm#cadillac Text of speech excerpt]}}
[[File:Project for the Development of National Highways of the United States.png|thumb|The Pershing Map]]
[[File:FDR Proposed Highways.jpg|thumb|FDR's hand-drawn map from 1938]]

The United States government's efforts to construct a national network of highways began on an ''ad hoc'' basis with the passage of the [[Federal Aid Road Act of 1916]], which provided $75&nbsp;million over a five-year period for [[matching funds]] to the states for the construction and improvement of highways.<ref>{{cite book |first = Carlos Arnaldo |last = Schwantes |title = Going Places: Transportation Redefines the Twentieth-Century West |location = Bloomington |publisher = Indiana University Press |year = 2003 |isbn = 9780253342027 |page = 142 }}</ref> The nation's revenue needs associated with [[World War I]] prevented any significant implementation of this policy, which expired in 1921.

In December 1918, E. J. Mehren, a civil engineer and the editor of ''[[Engineering News-Record]]'', presented his "A Suggested National Highway Policy and Plan"<ref name="mehren">{{cite magazine |first = E.J. |last = Mehren |title = A Suggested National Highway Policy and Plan |magazine = [[Engineering News-Record]] |date = December 19, 1918 |volume = 81 |issue = 25 |pages = 1112–1117 |url = https://books.google.com/books?id=d7tCAQAAMAAJ&q=%22A+suggested+national+highway+policy+and+plan%22+Dec.+19+1918&pg=PA1109 |issn = 0891-9526 |access-date = August 17, 2015 |via = [[Google Books]] }}</ref> during a gathering of the State Highway Officials and Highway Industries Association at the Congress Hotel in Chicago.<ref>{{cite web |first = Richard |last = Weingroff |date = October 15, 2013 |publisher = Federal Highway Administration |title = 'Clearly Vicious as a Matter of Policy': The Fight Against Federal-Aid |url = https://www.fhwa.dot.gov/infrastructure/hwyhist04a.cfm |access-date = August 17, 2015 |archive-url = https://web.archive.org/web/20150924032716/http://www.fhwa.dot.gov/infrastructure/hwyhist04a.cfm |archive-date = September 24, 2015 |url-status = live }}</ref> In the plan, Mehren proposed a {{convert|50,000|mi|km|adj=on}} system, consisting of five east–west routes and 10 north–south routes. The system would include two percent of all roads and would pass through every state at a cost of {{convert|25,000|$/mi|$/km}}, providing commercial as well as military transport benefits.<ref name= "mehren" />

In 1919, the US Army sent an expedition across the US to determine the difficulties that military vehicles would have on a cross-country trip. Leaving from [[the Ellipse]] near the [[White House]] on July 7, the [[1919 Motor Transport Corps convoy|Motor Transport Corps convoy]] needed 62 days to drive {{convert|3,200|mi|km}} on the [[Lincoln Highway]] to the [[Presidio of San Francisco]] along the [[Golden Gate]]. The convoy suffered many setbacks and problems on the route, such as poor-quality bridges, broken crankshafts, and engines clogged with desert sand.<ref name="Watson article on Motor Transport convoy">{{cite magazine |last1 = Watson |first1 = Bruce |title = Ike's Excellent Adventure |magazine = American Heritage |volume = 65 |issue = 4 |date = July–August 2020 |url = https://www.americanheritage.com/ikes-excellent-adventure |access-date = July 9, 2020 |archive-date = July 9, 2020 |archive-url = https://web.archive.org/web/20200709110417/https://www.americanheritage.com/ikes-excellent-adventure |url-status = live }}</ref>

[[Dwight D. Eisenhower|Dwight Eisenhower]], then a 28-year-old [[Brevet (military)|brevet]] lieutenant colonel,<ref>{{cite book |last = Ambrose |first = Stephen |year = 1983 |title = Eisenhower: Soldier, General of the Army, President-Elect (1893–1952) |volume = 1 |location = New York |publisher = Simon & Schuster }}{{page needed|date=December 2021}}</ref> accompanied the trip "through darkest America with truck and tank," as he later described it. Some roads in the West were a "succession of dust, ruts, pits, and holes."<ref name="Watson article on Motor Transport convoy" />

As the landmark 1916 law expired, new legislation was passed—the [[Federal Aid Highway Act of 1921]] (Phipps Act). This new road construction initiative once again provided for federal matching funds for road construction and improvement, $75&nbsp;million allocated annually.<ref name="schwantes152">{{harvp|ps=.|Schwantes|2003|p=152}}</ref> Moreover, this new legislation for the first time sought to target these funds to the construction of a national road grid of interconnected "primary highways", setting up cooperation among the various state highway planning boards.<ref name="schwantes152" />

The [[Federal Highway Administration|Bureau of Public Roads]] asked the [[United States Army|Army]] to provide a list of roads that it considered necessary for national defense.<ref>{{cite book |last = McNichol |first = Dan |year = 2006a |title = The Roads That Built America: The Incredible Story of the U.S. Interstate System |location = New York |publisher = Sterling |isbn = 978-1-4027-3468-7 |page = 87 }}</ref> In 1922, General [[John J. Pershing]], former head of the [[American Expeditionary Force]] in Europe during the war, complied by submitting a detailed network of {{convert|20,000|mi|km}} of interconnected primary highways—the so-called [[Pershing Map]].<ref>{{harvp|ps=.|Schwantes|2003|p=153}}</ref>

A boom in road construction followed throughout the decade of the 1920s, with such projects as the [[Parkways in New York State|New York parkway system]] constructed as part of a new national highway system. As automobile traffic increased, planners saw a need for such an interconnected national system to supplement the existing, largely non-freeway, [[United States Numbered Highways]] system. By the late 1930s, planning had expanded to a system of new superhighways.

{{Wikisource-multi|object=section|leading=2px|Toll Roads and Free Roads |Interregional Highways}}
In 1938, President [[Franklin D. Roosevelt]] gave [[Thomas Harris MacDonald|Thomas MacDonald]], chief at the Bureau of Public Roads, a hand-drawn map of the United States marked with eight superhighway corridors for study.<ref>{{harvp|ps=.|McNichol|2006a|p=78}}</ref> In 1939, Bureau of Public Roads Division of Information chief [[Herbert S. Fairbank]] wrote a report called ''Toll Roads and Free Roads'', "the first formal description of what became the Interstate Highway System" and, in 1944, the similarly themed ''Interregional Highways''.<ref>{{cite magazine |last = Weingroff |first = Richard F. |title = The Federal-State Partnership at Work: The Concept Man |magazine = Public Roads |volume = 60 |issue = 1 |date = Summer 1996 |url = http://www.tfhrc.gov/pubrds/summer96/p96su7b.htm#9 |access-date = March 16, 2012 |issn = 0033-3735 |archive-url = https://web.archive.org/web/20100528132734/http://www.tfhrc.gov/pubrds/summer96/p96su7b.htm#9 |archive-date = May 28, 2010 |url-status = dead }}</ref>

===Federal Aid Highway Act of 1956===
{{Main|Federal Aid Highway Act of 1956}}

The Interstate Highway System gained a champion in President Dwight D. Eisenhower, who was influenced by his experiences as a young Army officer crossing the country in the 1919 Motor Transport Corps convoy that drove in part on the [[Lincoln Highway]], the first road across America. He recalled that, "The old convoy had started me thinking about good two-lane highways... the wisdom of broader ribbons across our land."<ref name="Watson article on Motor Transport convoy" /> Eisenhower also gained an appreciation of the [[Reichsautobahn]] system, the first "national" implementation of modern Germany's [[German autobahns|Autobahn]] network, as a necessary component of a national defense system while he was serving as [[Supreme Commander of the Allied Expeditionary Force|Supreme Commander]] of [[Allies of World War II|Allied Forces]] in Europe during [[European Theatre of World War II|World War II]].<ref>{{cite magazine |title = On the Road |first = Henry |last = Petroski |magazine = American Scientist |volume = 94 |issue = 5 |year = 2006 |pages = 396–369 |issn = 0003-0996 |doi = 10.1511/2006.61.396 }}</ref> In 1954, Eisenhower appointed General [[Lucius D. Clay]] to head a committee charged with proposing an interstate highway system plan.<ref>{{cite book |last = Smith |first = Jean Edward |author-link = Jean Edward Smith |title = Eisenhower in War and Peace |publisher = Random House |isbn = 978-1400066933 |date = 2012 |page = 652 }}</ref> Summing up motivations for the construction of such a system, Clay stated,
{{Blockquote|It was evident we needed better highways. We needed them for safety, to accommodate more automobiles. We needed them for defense purposes, if that should ever be necessary. And we needed them for the economy. Not just as a public works measure, but for future growth.<ref>{{harvp|Smith|2012|pp=652–653|ps=.}}</ref>}}
{{Wikisource-multi|object=section|leading=2px| National Highway Program| A 10-Year National Highway Program |General Location of National System of Interstate Highways}}

Clay's committee proposed a 10-year, $100&nbsp;billion program {{USDCY|100000000000|1954}}, which would build {{convert|40,000|mi|km}} of [[Dual carriageway|divided highways]] linking all American cities with a population of greater than 50,000. Eisenhower initially preferred a system consisting of [[toll road]]s, but Clay convinced Eisenhower that toll roads were not feasible outside of the highly populated coastal regions. In February 1955, Eisenhower forwarded Clay's proposal to Congress. The bill quickly won approval in the Senate, but House Democrats objected to the use of public [[Bond (finance)|bonds]] as the means to finance construction. Eisenhower and the House Democrats agreed to instead finance the system through the [[Highway Trust Fund]], which itself would be funded by a [[gasoline]] tax.<ref>{{harvp|Smith|2012|pp=651–654|ps=.}}</ref> In June 1956, Eisenhower signed the [[Federal Aid Highway Act of 1956]] into law. Under the act, the federal government would pay for 90 percent of the cost of construction of Interstate Highways. Each Interstate Highway was required to be a [[freeway]] with at least four lanes and no at-grade crossings.<ref>{{cite web |title = The Interstate Highway System |url = https://www.history.com/topics/us-states/interstate-highway-system |website = History |publisher = A&E Television Networks |access-date = May 10, 2019 |archive-url = https://web.archive.org/web/20190510175042/https://www.history.com/topics/us-states/interstate-highway-system |archive-date = May 10, 2019 |url-status = live }}</ref>

The publication in 1955 of the ''General Location of National System of Interstate Highways'', informally known as the ''Yellow Book'', mapped out what became the Interstate Highway System.<ref>{{cite web |url = http://etext.virginia.edu/journals/EH/EH38/Norton.html |title = Fighting Traffic: U.S. Transportation Policy and Urban Congestion, 1955–1970 |last = Norton |first = Peter |year = 1996 |access-date = January 17, 2008 |work = Essays in History |publisher = Corcoran Department of History at the University of Virginia |url-status = dead |archive-url = https://web.archive.org/web/20080215220316/http://etext.virginia.edu/journals/EH/EH38/Norton.html |archive-date = February 15, 2008 }}</ref> Assisting in the planning was [[Charles Erwin Wilson]], who was still head of [[General Motors]] when President Eisenhower selected him as Secretary of Defense in January 1953.

===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>

===1992–present===

====Discontinuities====
{{Main|List of gaps in Interstate Highways}}
[[File:Eisenhower Interstate System sign.jpg|thumb|left|Commemorative sign introduced in 1993. The system was established during Dwight D. Eisenhower's presidency, and the five stars commemorate his rank as [[General of the Army (United States)|General of the Army]] during World War II.]]

The system was proclaimed complete in 1992, but two of the original Interstates—[[Interstate 95|I-95]] and [[Interstate 70|I-70]]—were not continuous: both of these discontinuities were due to local opposition, which blocked efforts to build the necessary connections to fully complete the system. I-95 was made a continuous freeway in 2018,<ref name="sofield">{{cite news |first = Tom |last = Sofield |date = September 22, 2018 |title = Decades in the Making, I-95, Turnpike Connector Opens to Motorists |url = http://levittownnow.com/2018/09/22/decades-in-the-making-i-95-turnpike-connector-opens-to-motorists/ |work = Levittown Now |access-date = September 22, 2018 |archive-date = April 6, 2020 |archive-url = https://web.archive.org/web/20200406195324/http://levittownnow.com/2018/09/22/decades-in-the-making-i-95-turnpike-connector-opens-to-motorists/ |url-status = live}}</ref> and thus I-70 remains the only original Interstate with a discontinuity.

I-95 was discontinuous in New Jersey because of the cancellation of the [[Somerset Freeway]]. This situation was remedied when the construction of the [[Pennsylvania Turnpike/Interstate 95 Interchange Project]] started in 2010<ref name="PA">{{cite web |author = Pennsylvania Turnpike Commission |date = n.d. |url = http://www.paturnpikei95.com/pdf/DACMeeting050914.pdf |publisher = Pennsylvania Turnpike Commission |work = I-95/I-276 Interchange Project Meeting Design Management Summary |title = Draft: Design Advisory Committee Meeting No. 2 |access-date = May 11, 2008 |archive-url = https://web.archive.org/web/20131002051518/http://www.paturnpikei95.com/pdf/DACMeeting050914.pdf |archive-date = October 2, 2013 |url-status = dead |author-link = Pennsylvania Turnpike Commission}}</ref> and partially opened on September 22, 2018, which was already enough to fill the gap.<ref name="sofield" />

However, I-70 remains discontinuous in [[Pennsylvania]], because of the lack of a direct interchange with the [[Pennsylvania Turnpike]] at the eastern end of the [[concurrency (road)|concurrency]] near [[Breezewood, Pennsylvania|Breezewood]]. Traveling in either direction, I-70 traffic must exit the freeway and use a short stretch of [[U.S. Route 30 in Pennsylvania|US&nbsp;30]] (which includes a number of roadside services) to rejoin I-70. The interchange was not originally built because of a legacy federal funding rule, since relaxed, which restricted the use of federal funds to improve roads financed with tolls.<ref name="Federal Highway Administration">{{cite web |author = Federal Highway Administration |url = https://www.fhwa.dot.gov/infrastructure/tollroad.cfm |title = Why Does The Interstate System Include Toll Facilities? |publisher = Federal Highway Administration |date = n.d. |access-date = July 15, 2009 |archive-url = https://web.archive.org/web/20130518082124/http://www.fhwa.dot.gov/infrastructure/tollroad.cfm |archive-date = May 18, 2013 |url-status = live }}</ref> Solutions have been proposed to eliminate the discontinuity, but they have been blocked by local opposition, fearing a loss of business.<ref>{{cite news |title = Dawida seeks to merge I-70, turnpike at Breezewood |first = Gary |last = Tuna |work = Pittsburgh Post-Gazette |date = July 27, 1989 |via = Google News |url = https://news.google.com/newspapers?id=O7RRAAAAIBAJ&pg=4854,6978383&dq=robert-jubelirer+breezewood&hl=en |access-date = November 19, 2015 |archive-url = https://web.archive.org/web/20150930132552/https://news.google.com/newspapers?id=O7RRAAAAIBAJ&sjid=Wm4DAAAAIBAJ&pg=4854,6978383&dq=robert-jubelirer+breezewood&hl=en |archive-date = September 30, 2015 |url-status = live }}</ref>

====Expansions and removals====
{{see also|Future Interstate Highways|Freeway removal}}
The Interstate Highway System has been expanded numerous times. The expansions have both created new designations and extended existing designations. For example, [[Interstate 49|I-49]], added to the system in the 1980s as a freeway in [[Louisiana]], was designated as an expansion corridor, and FHWA approved the expanded route north from [[Lafayette, Louisiana]], to [[Kansas City, Missouri]]. The freeway exists today as separate completed segments, with segments under construction or in the planning phase between them.<ref>{{cite web |url = http://www.modot.org/southwest_archive/I-49MapsandInformation.htm |author = Missouri Department of Transportation |date = n.d. |publisher = Missouri Department of Transportation |work = Interstate I-49 Expansion Corridor in Southwest District of Missouri |title = Converting US Route 71 to I-49 |url-status = dead |archive-url = https://web.archive.org/web/20130117094333/http://www.modot.org/southwest_archive/I-49MapsandInformation.htm |archive-date = January 17, 2013 |author-link = Missouri Department of Transportation }}</ref>

In 1966, the FHWA designated the entire Interstate Highway System as part of the larger [[Pan-American Highway]] System,<ref>{{cite book |author = New Mexico State Highway and Transportation Department |url = http://www.nmshtd.state.nm.us/upload/contents/445/Memorial.pdf |title = State of New Mexico Memorial Designations and Dedications of Highways, Structures and Buildings |year = 2007 |location = Santa Fe |publisher = New Mexico State Highway and Transportation Department |page = 14 |url-status = dead |archive-url = https://web.archive.org/web/20110716081405/http://www.nmshtd.state.nm.us/upload/contents/445/Memorial.pdf |archive-date = July 16, 2011 |author-link = New Mexico State Highway and Transportation Department }}</ref> and at least two proposed Interstate expansions were initiated to help trade with Canada and Mexico spurred by the [[North American Free Trade Agreement]] (NAFTA). Long-term plans for [[Interstate 69|I-69]], which currently exists in several separate completed segments (the largest of which are in [[Indiana]] and [[Texas]]), is to have the highway route extend from [[Tamaulipas]], Mexico to [[Ontario]], Canada. The planned [[Interstate 11|I-11]] will then bridge the Interstate gap between [[Phoenix, Arizona]] and [[Las Vegas, Nevada]], and thus form part of the [[CANAMEX Corridor]] (along with [[Interstate 19|I-19]], and portions of [[Interstate 10|I-10]] and [[Interstate 15|I-15]]) between [[Sonora]], Mexico and [[Alberta]], Canada.

===Opposition, cancellations, and removals===
{{more citations needed section|date=March 2015}}
{{main|Highway revolts in the United States}}
[[File:Interstate_81_elevated_syracuse_E_Genesee_St.jpg|thumb|right|300px|alt=Photograph of Interstate 81, carried on an aging viaduct through the middle of Syracuse, New York|The fervor of [[urban renewal]] led to the routing of [[Interstate 81 in New York|Interstate 81]] through the middle of [[Syracuse, New York|Syracuse's]] 15th Ward in the 1960s. The viaduct is now slated for demolition.<ref name=WalkerCurbed>{{cite news|last=Walker|first=Alissa|title=About Time: Syracuse's I-81 Is Finally Being Demolished|url=https://www.curbed.com/2022/01/hochul-syracuse-highway-removal-i-81.html|date=2022|work=Curbed|archive-date=March 29, 2024|access-date=March 29, 2024|archive-url=https://web.archive.org/web/20240329141055/https://www.curbed.com/2022/01/hochul-syracuse-highway-removal-i-81.html|url-status=live}}</ref>]]
Political opposition from residents canceled many freeway projects around the United States, including:
* [[Interstate 40 in Tennessee|I-40]] in Memphis, Tennessee was rerouted and part of the original I-40 is still in use as the eastern half of [[Sam Cooper Boulevard]].<ref>{{harvp|ps=.|McNichol|2006a|pp=159–160}}</ref>
* [[Interstate 66|I-66]] in the [[District of Columbia]] was abandoned in 1977.
* [[Interstate 69|I-69]] was to continue past its terminus at Interstate 465 to intersect with [[Interstate 70]] and [[Interstate 65]] at the north split, northeast of downtown [[Indianapolis]]. Though local opposition led to the cancellation of this project in 1981, bridges and ramps for the connection into the "north split" remained until it was rebuilt in 2023.
* [[Interstate 70 in Maryland|I-70]] in [[Baltimore]] was supposed to run from the Baltimore Beltway ([[Interstate 695 in Maryland|Interstate 695]]), which surrounds the city to terminate at [[I-95]], the East Coast thoroughfare that runs through Maryland and Baltimore on a diagonal course, northeast to southwest; the connection was cancelled on the mid-1970s due to its routing through [[Gwynns Falls Leakin Park|Gwynns Falls-Leakin Park]], a wilderness urban park reserve following the [[Gwynns Falls]] stream through West Baltimore. This included the cancellation of [[Interstate 170 (Maryland)|I-170]], partially built and in use as US&nbsp;40, and nicknamed the Highway to Nowhere.  The freeway stub of I-70 inside the Beltway was renumbered MD&nbsp;570 in 2014, but continues to bear I-70 signs.
* [[Interstate 78 in New York|I-78]] in New York City was canceled along with portions of [[Interstate 278|I-278]], [[Interstate 478|I-478]], and [[Interstate 878|I-878]]. I-878 was supposed to be part of I-78, and I-478 and I-278 were to be spur routes.
* [[Interstate 80 in California|I-80]] in San Francisco was originally planned to travel past the city's Civic Center along the Panhandle Freeway into [[Golden Gate Park]] and terminate at the original alignment of [[Interstate 280 (California)|I-280]]/[[California State Route 1|SR 1]]. The city canceled this and several other freeways in 1958. Similarly, more than 20 years later, Sacramento canceled plans to upgrade I-80 to Interstate Standards and rerouted the freeway on what was then I-880 that traveled north of Downtown Sacramento.
* [[Interstate 83|I-83]], southern extension of the [[Jones Falls Expressway]] (southern [[I-83]]) in [[Baltimore]] was supposed to run along the waterfront of the [[Patapsco River]] / [[Helen Delich Bentley Port of Baltimore|Baltimore Harbor]] to connect to [[Interstate 95 in Maryland|I-95]], bisecting historic neighborhoods of [[Fells Point, Baltimore|Fells Point]] and [[Canton, Baltimore|Canton]], but the connection was never built.
* [[Interstate 84 (Pennsylvania-Massachusetts)|I-84]] in [[Connecticut]] was once planned to fork east of Hartford, into an [[Interstate 84 (Pennsylvania–Massachusetts)|I-86]] to Sturbridge, Massachusetts, and I-84 to Providence, R.I. The plan was cancelled, primarily because of anticipated impact on a major Rhode Island reservoir. The I-84 designation was restored to the highway to Sturbridge, and other numbering was used for completed Eastern sections of what had been planned as part of I-84.
* [[Interstate 95 in Maryland|I-95]] through the [[District of Columbia]] into [[Maryland]] was abandoned in 1977. Instead it was rerouted to [[Interstate 495 (Capital Beltway)|I-495 (Capital Beltway)]]. The completed section is now [[Interstate 395 (Virginia–District of Columbia)|I-395]].
* [[Interstate 95 in Massachusetts|I-95]] was originally planned to run up the [[Southwest Corridor (Massachusetts)|Southwest Expressway]] and meet [[Interstate 93|I-93]], where the two highways would travel along the [[Central Artery]] through downtown [[Boston]], but was rerouted onto the [[Massachusetts State Highway 128|Route 128]] beltway due to widespread opposition. This revolt also included the cancellation of the [[Interstate 695 (Massachusetts)|Inner Belt]], connecting I-93 to [[Massachusetts Turnpike|I-90]] and a cancelled section of the [[U.S. Route 3|Northwest Expressway]] which would have carried [[U.S. Route 3|US&nbsp;3]] inside the Route 128 beltway, meeting with [[Massachusetts Route 2|Route 2]] in [[Cambridge, Massachusetts|Cambridge]].

In addition to cancellations, removals of freeways are planned:
* [[Interstate 81 in New York|I-81]] in [[Syracuse, New York]], which bisects the city's 15th Ward neighborhood, is planned to be torn down and replaced with a [[boulevard]] that accommodates pedestrians.<ref name=WalkerCurbed /><ref name=ZarroliNYT>{{cite news|last=Zarroli|first=Jim|work=New York Times|url=https://www.nytimes.com/2023/06/03/nyregion/syracuse-interstate-81.html|date=2023|title=Why It's So Hard to Tear Down a Crumbling Highway Nearly Everyone Hates}}</ref> Freeway traffic would be rerouted along [[I-481]].<ref name=ZarroliNYT />