The Dwight D. Eisenhower National System of Interstate and Defense Highways, commonly known as the Interstate Highway System, or the Eisenhower Interstate System, is a network of controlled-access highways that forms part of the National Highway System in the United States. The system extends throughout the contiguous United States and has routes in Hawaii, Alaska, and Puerto Rico.
The United States Numbered Highway System is an integrated network of roads and highways numbered within a nationwide grid in the contiguous United States. As the designation and numbering of these highways were coordinated among the states, they are sometimes called Federal Highways, but the roadways were built and have always been maintained by state or local governments since their initial designation in 1926.
In Missouri, odd-numbered highways run north-south and even-numbered highways run east-west. Missouri also maintains a secondary set of roads, supplemental routes, which are lettered rather than numbered.
U.S. Route 50 or U.S. Highway 50 (US 50) is a major east–west route of the U.S. Highway system, stretching 3,019 miles (4,859 km) from Interstate 80 (I-80) in West Sacramento, California, to Maryland Route 528 in Ocean City, Maryland, on the Atlantic Ocean. Until 1972, when it was replaced by Interstate Highways west of the Sacramento area, it extended to San Francisco, near the Pacific Ocean. The Interstates were constructed later and are mostly separate from this route. It generally serves a corridor south of I-70 and I-80 and north of I-64 and I-40.
The Ohio Department of Transportation (ODOT) is responsible for the establishment and classification of a state highway network which includes interstate highways, U.S. highways, and state routes. As with other states, U.S. and Interstate highways are classified as state routes in Ohio. There are no state routes which duplicate an existing U.S. or Interstate highway in Ohio.
A concurrency in a road network is an instance of one physical roadway bearing two or more different route numbers. When two roadways share the same right-of-way, it is sometimes called a common section or commons. Other terminology for a concurrency includes overlap, coincidence, duplex, triplex, multiplex, dual routing or triple routing.
Interstate 225 (I-225) is an auxiliary Interstate Highway in the U.S. state of Colorado. The freeway is a 11.959-mile-long (19.246 km) connector spur route of I-25 that acts as an eastern bypass in the Denver metropolitan area and serves Aurora. It also provides direct access to Denver International Airport for the Denver Tech Center and the southern suburbs of Denver. I-225 is one of the two existing auxiliary Interstate Highways in Colorado and it is the only auxiliary route of I-25, as there are no auxiliary routes for I-25 in New Mexico and Wyoming. The route begins at I-25 in the Denver Tech Center and runs north to I-70 north of Aurora. It interchanges with State Highway 83 (SH 83), SH 30 and I-70 Business/US 40/US 287, known locally as Colfax Avenue. The freeway was first proposed in the 1950s along with the first Interstate Highways within Denver. Construction did not begin until 1964 at the I-70 interchange and proceeded south through Aurora until final completion in early 1976 with the final link to I-25 opening to traffic.
The state highway system of the U.S. state of Oregon is a network of highways that are owned and maintained by the Highway Division of the Oregon Department of Transportation (ODOT).
Texas state highways are a network of highways owned and maintained by the U.S. state of Texas. The Texas Department of Transportation (TxDOT) is the state agency responsible for the day-to-day operations and maintenance of the system. Texas has the largest state highway system, followed closely by North Carolina's state highway system. In addition to the nationally numbered Interstate Highways and U.S. Highways, the highway system consists of a main network of state highways, loops, spurs, and beltways that provide local access to the other highways. The system also includes a large network of farm to market roads that connect rural areas of the state with urban areas and the rest of the state highway system. The state also owns and maintains some park and recreational roads located near and within state and national parks, as well as recreational areas. All state highways, regardless of classification, are paved roads. The Old San Antonio Road, also known as the El Camino Real, is the oldest highway in the United States, first being blazed in 1691. The length of the highways varies from US 83's 893.4 miles (1,437.8 km) inside the state borders to Spur 200 at just 0.05 miles long.
Interstate 270 (I-270) is a seven-mile-long (11 km) auxiliary Interstate Highway located in the northeastern part of the Denver metropolitan area in the US state of Colorado. It overlaps U.S. Highway 36 (US 36) for its entire length and is also a part of the Dwight D. Eisenhower Highway, which spans from I-270 and the Capital Beltway in Bethesda, Maryland, to I-80/US 101 in San Francisco, California. The western terminus of I-270 is at the interchange with I-25 and US 36. It heads eastward to an interchange with I-76, where the mileposts reset because of a previous freeway extension. The freeway heads southeast and comes to meet Vasquez Boulevard, where it enters Commerce City. The road crosses Quebec Street before ending at I-70.
U.S. Highway 75 (US 75) is a part of the U.S. Highway System that travels from Interstate 345 (I-345) in Dallas, Texas northward to the Canadian border at Noyes, Minnesota. In the state of Texas it runs from I-345 in Dallas and heads north to the Oklahoma state line.
In the U.S. state of Pennsylvania, state highways are generally maintained by the Pennsylvania Department of Transportation (PennDOT). Each is assigned a four-digit State Route (SR) number in the present Location Referencing System. Traffic Routes are signed as Interstate Highways, U.S. Routes and Pennsylvania Routes, and are prefixed with one to three zeroes to give a four-digit number. PA Routes are also called Pennsylvania Traffic Routes, and formerly State Highway Routes.
U.S. Route 95 (US 95) is a United States Numbered Highway, stretching from the Mexican border in San Luis, Arizona to the Canadian border near Eastport, Idaho. The California portion of US 95 traverses through the far eastern edges of both Riverside and San Bernardino counties. US 95 serves Blythe and Needles and junctions with SR 62 at Vidal Junction.
Interstate business routes are roads connecting a central or commercial district of a city or town with an Interstate bypass. These roads typically follow along local streets often along a former US or state highway that had been replaced by an Interstate. Interstate business route reassurance markers are signed as either loops or spurs using a green shield shaped sign and numbered like the shield of the parent Interstate Highway.
Interstate 87 (I-87) is a partially completed Interstate Highway in the US state of North Carolina, the shortest designated primary Interstate Highway at 12.90 miles (20.76 km). The completed portion is in eastern Wake County, between Raleigh and Wendell; the majority of the completed route is known as the Knightdale Bypass, while the remaining three miles (4.8 km) follows the Raleigh Beltline (I-440). It is planned to continue northeast through Rocky Mount, Williamston, and Elizabeth City, ending in Norfolk, Virginia. It is signed as north–south, in keeping with the sign convention for most odd-numbered interstates, but the route goes primarily east–west, with the eastern direction aligning to the north designation. The entire route is concurrent with US Highway 64 (US 64), with portions also concurrent with I-440 and US 264.
The Delaware State Route System consists of roads in the U.S. state of Delaware that are maintained by the Delaware Department of Transportation (DelDOT). The system includes the portions of the Interstate Highway System and United States Numbered Highways system located in the state along with state routes and other roads maintained by DelDOT. All roads maintained by the state are assigned a maintenance road number that is only marked on little white markers at intersections and on auxiliary plates below warning signs approaching intersections. These numbers are only unique in a specific county; some roads can be designated with multiple road numbers, and numbers do not necessarily correspond to the signed Interstate, U.S., or state route numbers. DelDOT maintains a total of 5,386.14 miles (8,668.15 km) of roads, comprising 89 percent of the roads within the state. Some large bridges in the state are maintained by other agencies including the U.S. Army Corps of Engineers and the Delaware River and Bay Authority. Roads in the system include multilane freeways, multilane surface divided highways, and two-lane undivided roads serving urban, suburban, and rural areas. Some of the roads maintained by DelDOT are toll roads, in which motorists must pay to use.
