![]() | This article possibly contains original research .(December 2024) |
Dwight D. Eisenhower National System of Interstate and Defense Highways | |
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![]() Interstate Highways in the 48 contiguous states | |
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-84s, 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 segments: the northernmost segment travels from near Evansville, Indiana, to Port Huron, Michigan. A second alignment located entirely within the state of Kentucky runs from the Tennessee state line at Fulton to Henderson. 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 2025, projects to connect these segments are in varying stages of development. Kentucky and Indiana began construction of the eastern bypass of Henderson and new Ohio River Crossing, connecting the Kentucky and Indiana sections, in 2022. [6] This segment has a tentative completion date of 2031. [7] Kentucky has plans to work with Tennessee to reconstruct the current interchange at the south end of their segment in South Fulton to provide a free-flow connection to the existing US 51 freeway to Union City. Tennessee finished constructing a bypass of Union City in 2021 currently designated as SR 690. [8] 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.