Dwight D. Eisenhower National System of Interstate and Defense Highways | |
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System information | |
Formed | June 29, 1956 [1] |
Highway names | |
Interstates | Interstate X (I-X) |
System links | |
There are gaps in the Interstate Highway system, where the roadway carrying an Interstate shield does not conform to the standards set by the Federal Highway Administration (FHWA), the body that sets the regulations for the Interstate Highway System. For the most part, the Interstate Highway System in the United States is a connected system, with most freeways completed; however, some Interstates still have gaps. These gaps can be due to unconnected segments of the same route or from failure of the road to fully conform to Interstate standards by including such characteristics as at-grade crossings, traffic lights, undivided or narrow freeways, or movable bridges (lift bridges and drawbridges).
True gaps are where multiple disjoint sections of road have the same Interstate highway number and can reasonably be considered part of "one highway" in theory, based on the directness of connections via other highways, or based on future plans to fill in the gap in the Interstate, or simply based on the shortness of the gap. The sections are either not physically connected at all, or they are connected but the connection is not signed as part of the highway. This list does not include different highways that share the same number, such as the two different I-76s, I-84s, I-86s, I-87s, and I-88s, which despite appearances, were always intended as distinct highways and were never intended as a contiguous route.
In North Carolina, Interstate 26 has a gap from Forks of Ivy to Asheville at exit 4A of Interstate 240. This is because not all of the parts in the gap were built to Interstate standards. As of November 2023, Interstate 26 is designated as Future I-26, US 19, and US 23. Construction on building this gap to Interstate Standards was scheduled to start in 2022. [2]
In North Carolina, Interstate 42 has a gap from Clayton to Goldsboro. This is because the corridor that the Interstate will be on is not up to standards or is unbuilt.[ citation needed ] North Carolina plans to complete I-42 by 2032.[ citation needed ]
Interstate 49 (I-49) currently has three sections: the original alignment from I-10 in Lafayette to I-20 in Shreveport, one from I-220 near Shreveport to Texarkana; and the third section from I-40 near Alma, Arkansas to I-470/I-435 south of Kansas City, Missouri. A bypass south of Bella Vista, Arkansas was completed in 2021, and existed initially as Arkansas Highway 549; the latter designation is now used on a short section southeast of Fort Smith that is several miles long. It is planned to be connected to an interstate with a project to construct a new roadway from Arkansas Highway 22 to Interstate 40 in Arkansas. I-49 from Fort Smith to Texarkana is still unbuilt. These gaps are expected to be eventually closed.
I-69 currently has several disconnected sections: the original alignment travels from Indianapolis, Indiana, to Port Huron, Michigan. A second section exists from near Evansville, Indiana, to Martinsville, Indiana south of Indianapolis. In stages from 2011 to 2018, sections of the Purchase Parkway, I-24, the Wendell H. Ford Western Kentucky Parkway, and the Pennyrile Parkway from Mayfield, Kentucky, to Henderson, Kentucky, became signed as I-69. On October 2, 2006, a segment of I-69 opened in Tunica and DeSoto counties in Mississippi; this segment has since been continued (but is not signed) through Memphis, Tennessee, to an intersection with U.S. Highway 51 on the north side. Between 2012 and 2015, a portion of U.S. Highway 59 (US 59) between Rosenberg and Cleveland, Texas, extending through Houston, became part of I-69. [3] [4] [5] In South Texas, I-69's route splits into three spurs to cities on the U.S.–Mexico border, on which four segments are complete: a short segment of I-69E in Corpus Christi and another from Raymondville to the border in Brownsville; a short segment of I-69C in Edinburg and McAllen; and a very short segment of I-69W adjacent to the border in Laredo.
As of 2021, projects to connect these segments are in varying stages of development. Indiana is currently working to connect the Port Huron–Indianapolis and Martinsville–Evansville sections by extending I-69 north from Martinsville to the I-465 Indianapolis loop, with construction completed in August 2024. [6] Kentucky and Indiana expect to begin construction of the eastern bypass of Henderson and new Ohio River crossing, connecting the Mayfield–Henderson and Martinsville–Evansville sections, in 2022. [7] Kentucky has plans to upgrade the remaining section of the Purchase Parkway and work with Tennessee to reconstruct the current interchange at the south end of the Purchase Parkway in South Fulton, Tennessee to provide a free-flow connection to the existing U.S. 51 freeway to Union City, while Tennessee finished I-69 bypass of Union City. [8] It is currently designated as SR 690. A further bypass of Troy is proposed but not yet funded, which would complete a freeway-standard route from I-155 in Dyersburg to Henderson. Tennessee has deferred plans to complete the section between Dyersburg and Memphis to close the gap until the South Fulton–Dyersburg section is completed. [9] The section from Memphis to Houston is the least developed; as of 2021, Mississippi has no current plans to extend I-69 further south, and the states of Louisiana and Arkansas have not funded construction of their portion of the proposed route (via El Dorado and Shreveport) between Mississippi and Texas, other than a two-lane southern bypass of Monticello, Arkansas designed to be incorporated into I-69 at a later date. Texas has continued to fund projects to upgrade U.S. 59, U.S. 77, U.S. 281, and other routes that would eventually form parts of I-69 in South Texas and East Texas, including the I-69W/C/E spurs.
I-74 currently has five sections, [10] the original segment heading northwest from Cincinnati, Ohio, to Davenport, Iowa; one from the Virginia–North Carolina line along I-77 south and east to a point southeast of Mount Airy, North Carolina; one traveling around High Point connecting with I-85 and reaching I-73, where the two are concurrent until Ellerbe; and from west of Laurinburg to south of Lumberton, North Carolina, at I-95. North Carolina is currently[ when? ] working on connecting all its sections of I-74.
The eastern I-86 has had two sections since 2006. One travels for 197 miles (317 km) from I-90 in North East, Pennsylvania (which is a town in the northwestern part of the state) to exit 61 in Waverly, New York. The second section is a 9.9-mile (15.9 km) stretch outside of Binghamton traveling from I-81 in Kirkwood to exit 79 in Windsor. The gap is signed as Future 86. I-86 will eventually travel from North East, Pennsylvania, to the New York State Thruway (I-87) near Harriman, New York. All the designated sections and gaps in New York are part of New York State Route 17.
As of 2023, I-99 has two sections: one from the Pennsylvania Turnpike to just south of I-80, concurrent with US 220, and one from the Pennsylvania–New York state line north to I-86 in Corning, New York, concurrent with US 15. Much of the intervening route, including the entire US 15 section between I-180 in Williamsport and the New York state line, has been constructed to freeway standards but as of yet is not signed as part of I-99.
The signing of the intervening route as I-99 will be completed when the route is upgraded to Interstate standards, connecting the two segments of I-99.
When the Francis Scott Key Bridge in Baltimore, Maryland, collapsed in 2024, a segment of I-695 would physically disappear for some time as a consequence of the bridge collapse. [11] At the time of the collapse, the section of highway was legally Maryland Route 695, but this section was redesignated I-695 by the American Association of State Highway and Transportation Officials in April 2024. [12]
Freeway gaps occur where the Interstate is signed as a continuous route, but part, if not all of it, is not up to freeway standards. This includes drawbridges where traffic on the Interstate can be stopped for vessels. This does not include facilities such as tollbooths, toll plazas, agricultural inspection stations, or border stations.
In urban and heavily developed areas, Interstates may travel along surface roads or have at-grade intersections with stop signs or traffic lights. This usually happens because the Interstate started construction after the land was heavily developed and buildings such as residences and businesses and other roads would have to be removed to allow a freeway to pass through. Additionally, more developed land would have to be cleared for space to build interchanges to connect the Interstate and surface streets. This situation is extremely uncommon as Interstates are usually built around cities or through them on pre- or lightly developed land.
Several Interstates in rural areas of the U.S. have minor at-grade intersections (including median breaks) with farm access roads or authorized vehicle-only driveways used for highway maintenance or connection to nearby utility stations. This is usually due to the lack of an old highway, the need to provide access to property that was accessed via the road prior to its upgrade to an Interstate, and the high cost to construct an interchange for the small amount of traffic that would use such a connection or to build a frontage road parallel to the freeway to the nearest interchange.
This section addresses two-lane freeways and other narrow or undivided freeway sections of the Interstate, excepting instances of continuing routes using one-lane ramps and merge leads. Narrow gaps between opposing directions with jersey barriers taller than four feet (1.2 m) are excluded from this section; therefore the separation criterion is really either a 4-foot-tall (1.2 m) wall, or a 100-foot-wide (30 m) median, whichever is greater.
By Interstate standard, all bridges on the Interstate system must be fixed as to not interrupt the flow of traffic. Several bridges on the system, however, are movable:
Auxiliary Interstates (also known as three-digit Interstates) are intended to connect to their parent either directly or via a same-parented Interstate (like I-280 in California being connected to I-80 via I-680). Often, these connection gaps occur to eliminate concurrencies between other three-digit routes. Freeway gaps (signed or unsigned) that officially connect auxiliary routes to the parent are excluded.
Interstate 95 (I-95) is the main north–south Interstate Highway on the East Coast of the United States, running from U.S. Route 1 (US 1) in Miami, Florida, north to the Houlton–Woodstock Border Crossing between Maine and the Canadian province of New Brunswick. The highway largely parallels the Atlantic coast and US 1, except for the portion between Savannah, Georgia, and Washington, D.C., and the portion between Portland and Houlton in Maine, both of which follow a more direct inland route.
Interstate 99 (I-99) is an interstate highway in the United States with two segments: one located in central Pennsylvania and the other in southern New York. The southern terminus of the route is near exit 146 of the Pennsylvania Turnpike (I-70/I-76) north of Bedford, where the road continues south as U.S. Route 220 (US 220). The northern terminus of the Pennsylvania segment is at an at-grade intersection with Musser Lane just before reaching I-80 near Bellefonte. The New York segment follows US 15 from the Pennsylvania–New York border to an interchange with I-86 in Corning. Within Pennsylvania, I-99 passes through Altoona and State College—the latter home to the Pennsylvania State University—and is entirely concurrent with US 220. Long-term plans call for the two segments of I-99 to be connected using portions of I-80, US 220, and US 15 through Pennsylvania.
Interstate 83 (I-83) is an Interstate Highway located in the states of Maryland and Pennsylvania in the Eastern United States. Its southern terminus is at a signalized intersection with Fayette Street in Baltimore, Maryland; its northern terminus is at I-81 near Harrisburg, Pennsylvania. I-83 runs from Downtown Baltimore north to I-695 near the northern suburb of Timonium on the Jones Falls Expressway before forming a concurrency with I-695. After splitting from I-695, the route follows the Baltimore–Harrisburg Expressway north to the border between Maryland and Pennsylvania. Upon crossing the state line, I-83 becomes the Veterans of Foreign Wars of the United States Memorial Highway and continues north through York toward the Harrisburg area. The route runs along the southern and eastern portion of the Capital Beltway that encircles Harrisburg before reaching its northern terminus.
U.S. Route 46 (US 46) is an east–west U.S. Highway completely within the state of New Jersey, running for 75.34 mi (121.25 km), making it the shortest signed, non-spur U.S. Highway. The west end is at an interchange with Interstate 80 (I-80) and Route 94 in Columbia, Warren County, on the Delaware River. The east end is in the middle of the George Washington Bridge over the Hudson River in Fort Lee, Bergen County, while the route is concurrent with I-95 and US 1-9. Throughout much of its length, US 46 is closely paralleled by I-80. US 46 is a major local and suburban route, with some sections built to or near freeway standards and many other sections arterials with jughandles. The route runs through several communities in the northern part of New Jersey, including Hackettstown, Netcong, Dover, Parsippany-Troy Hills, Wayne, Clifton, Ridgefield Park, Palisades Park, and Fort Lee. It crosses over the Upper Passaic River at several points. The road has been ceremonially named the United Spanish–American War Veterans Memorial Highway.
U.S. Route 202 (US 202) is a spur route of US 2. It follows a northeasterly and southwesterly direction stretching from Delaware in the south to Maine in the north and traveling through the states of Pennsylvania, New Jersey, New York, Connecticut, Massachusetts, and New Hampshire. The highway has borne the number 202 since at least 1936. Before this, sections of the highway were designated U.S. Route 122, as it intersected US 22 in New Jersey. It intersects its parent route, US 2, in Bangor, Maine.
Interstate 376 (I-376) is a major auxiliary route of the Interstate Highway System in the US state of Pennsylvania, located within the Allegheny Plateau. It runs from I-80 near Sharon south and east to a junction with the Pennsylvania Turnpike in Monroeville, after having crossed the Pennsylvania Turnpike at an interchange in Big Beaver. The route serves Pittsburgh and its surrounding areas and is the main access road to Pittsburgh International Airport (PIT). Portions of the route are known as the Beaver Valley Expressway, Southern Expressway, and Airport Parkway. Within Allegheny County, the route runs along the majority of the Penn-Lincoln Parkway, known locally as Parkway West and Parkway East. It is currently the ninth-longest auxiliary Interstate route in the system and second only to I-476 within Pennsylvania.
Interstate 495 (I-495) is an auxiliary route of I-95 in the US state of Massachusetts, maintained by the Massachusetts Department of Transportation (MassDOT). Spanning 121.56 miles (195.63 km), it is the second-longest auxiliary route in the Interstate Highway System, being roughly 11 miles (18 km) shorter than I-476 in Pennsylvania.
Interstate 530 (I-530) in Arkansas is a spur route of the Interstate highway system, traveling 46.65 miles (75.08 km) from Pine Bluff north-northwest to Little Rock at an interchange of I-30/I-440/U.S. Highway 65 (US 65)/US 67/US 167. The highway also travels through the cities of Redfield and White Hall. In the future, I-530 will be extended to I-69 west of Monticello. A short section near the future I-69 alignment has been signed as Highway 530 (AR 530).
Interstate 295 (I-295) in Delaware, New Jersey, and Pennsylvania is an auxiliary Interstate Highway, designated as a bypass around Philadelphia, and a partial beltway of Trenton.
U.S. Route 422 (US 422) is a 271-mile-long (436 km) spur route of US 22 split into two segments in the U.S. states of Ohio and Pennsylvania. The western segment of US 422 runs from downtown Cleveland, Ohio, east to Ebensburg, Pennsylvania. The eastern segment, located entirely within Pennsylvania, runs from Hershey east to King of Prussia, near Philadelphia. US 422 Business serves as a business route into each of four towns along the way.
Interstate 95 (I-95) is a major Interstate Highway that runs along the East Coast of the United States from Miami, Florida, north to the Canada–United States border at Houlton, Maine. In New Jersey, it runs along much of the mainline of the New Jersey Turnpike, as well as the Pearl Harbor Memorial Turnpike Extension, and the New Jersey Turnpike's I-95 Extension to the George Washington Bridge for a total of 77.96 miles (125.46 km). Located in the northeastern part of the state near New York City, the 11.03-mile (17.75 km) Western Spur of the New Jersey Turnpike, considered to be Route 95W by the New Jersey Department of Transportation (NJDOT), is also part of I-95.
Interstate 78 (I-78) is an east–west route stretching from Union Township, Lebanon County, Pennsylvania, to New York City. In New Jersey, I-78 is called the Phillipsburg–Newark Expressway and the Newark Bay Extension of the New Jersey Turnpike. The highway runs for 67.8 miles (109.1 km) in the northern part of the state of New Jersey from the I-78 Toll Bridge over the Delaware River at the Pennsylvania state line in Phillipsburg, Warren County, east to the Holland Tunnel under the Hudson River at the New York state line in Jersey City, Hudson County. The Phillipsburg–Newark Expressway portion of I-78, formally called the Lightning Division Memorial Highway, runs from the Phillipsburg area east across rural areas of Western New Jersey before entering suburban areas in Somerset County. The road crosses the Watchung Mountains, widening into a local–express lane configuration at Route 24 as it continues through urban areas to Newark. Here, I-78 intersects the mainline of the New Jersey Turnpike (I-95) and becomes the Newark Bay Extension, crossing the Newark Bay Bridge and continuing to Jersey City. The route, along with Route 139, follows a one-way pair of surface streets to the Holland Tunnel.
U.S. Route 30 (US 30) is a U.S. Highway that runs east–west across the southern part of Pennsylvania, passing through Pittsburgh and Philadelphia on its way from the West Virginia state line east to the Benjamin Franklin Bridge over the Delaware River into New Jersey.
The Mon–Fayette Expressway is a partially-completed controlled-access toll road that is planned to eventually link Interstate 68 near Morgantown, West Virginia with Interstate 376 near Monroeville, Pennsylvania. The ultimate goal of the highway is to provide a high speed north–south connection between Morgantown and the eastern side of Pittsburgh while revitalizing economically distressed Monongahela River Valley towns in Fayette and Washington counties, serving as an alternative to Interstate 79 to the west, as well as relieving the PA 51 alignment from Pittsburgh to Uniontown.
Pennsylvania Route 283 (PA 283), officially State Route 0300 or SR 0300 due to the presence of Interstate 283 (I-283), is a 29-mile-long (47 km) freeway in the U.S. state of Pennsylvania. It connects Harrisburg to Lancaster, paralleling the old U.S. Route 230. The route follows a generally northwest–southeast direction but is signed east–west. The number was assigned based on the function the route serves as a southeastern extension of I-283, but I-283 and PA 283 are not the same roadway; the two intersect at a partial cloverleaf interchange.
Interstate 70 (I-70) is an Interstate Highway that is located in the Commonwealth of Pennsylvania in the United States. It runs east to west across the southwest part of Pennsylvania and serves the southern fringe of the Pittsburgh metropolitan area.
Interstate 95 (I-95) is a major north–south Interstate Highway that runs along the East Coast of the United States from Miami, Florida, north to the Canada–United States border at Houlton, Maine. In the state of Pennsylvania, it runs 51.00 miles (82.08 km) from the Delaware state line near Marcus Hook in Delaware County in the southeastern part of the state northeast to the Delaware River–Turnpike Toll Bridge at the New Jersey state line near Bristol in Bucks County, closely paralleling the New Jersey state line for its entire length through Pennsylvania.
A two-lane expressway or two-lane freeway is an expressway or freeway with only one lane in each direction, and usually no median barrier. It may be built that way because of constraints, or may be intended for expansion once traffic volumes rise. The term super two is often used by roadgeeks for this type of road, but traffic engineers use that term for a high-quality surface road. Most of these roads are not tolled.
U.S. Route 1 (US 1) is a U.S. Route which parallels the East Coast of the United States, running from Key West, Florida, in the south to Fort Kent, Maine, at the Canadian border in the north. Of the entire length of the route, 66.06 miles (106.31 km) of it runs through New Jersey. It enters the state from Pennsylvania on the Trenton–Morrisville Toll Bridge over the Delaware River in the state capital of Trenton, running through the city on the Trenton Freeway. From here, US 1 continues northeast as a surface divided highway through suburban areas, heading into Middlesex County and passing through New Brunswick and Edison. US 1 merges with US 9 in Woodbridge, and the two routes continue through northern New Jersey as US 1/9 to the George Washington Bridge over the Hudson River in Fort Lee. At this point, the road continues into New York City along with Interstate 95.
Highway revolts have occurred in cities and regions across the United States. In many cities, there remain unused highways, abruptly terminating freeway alignments, and short stretches of freeway in the middle of nowhere, all of which are evidence of larger projects which were never completed. In some instances, freeway revolts have led to the eventual removal or relocation of freeways that had been built.