How many interstates are there in the USA?
List of Interstate Highways
There are 70 primary Interstate Highways in the Interstate Highway System, a network of controlled-access freeways in the United States. They are assigned one- or two-digit route numbers, whereas their associated "auxiliary" Interstate Highways receive three-digit route numbers. Typically, odd-numbered Interstates run south-north, with lower numbers in the west and higher numbers in the east; even-numbered Interstates run west-east, with lower numbers in the south and higher numbers in the north. Highways whose route numbers are divisible by "5" usually represent major coast-to-coast or border-to-border routes (ex. I-10 travels from Santa Monica, California, to Jacksonville, Florida, traveling from the Pacific to Atlantic oceans). Additionally, auxiliary highways have their numbering system where a different number prefixes the number of its parent highway.
Highway
The United States has the world's largest network of highways, including both the Interstate Highway System and the U.S. Highway System. At least one of these networks is present in every state and they interconnect most major cities.
Interstate 95
With a length of , I-95 is the longest north–south Interstate and the sixth-longest Interstate Highway overall. I-95 passes through more states than any other Interstate Highway at 15 states (as well as a very brief stretch in the District of Columbia while crossing the Potomac River), followed by I-90, which crosses 13 states. According to the U.S. Census Bureau, only five of the 96 counties (or equivalents) along the route are completely rural, while statistics provided by the I-95 Corridor Coalition suggest that the region served is "over three times more densely populated than the U.S. average and as densely settled as much of Western Europe". According to the Corridor Coalition, I-95 serves 110 million people and facilitates 40 percent of the country’s gross domestic product.
List of Interstate Highways in North Carolina
There are 17 Interstate Highways—7 primary and 10 auxiliary—that exist entirely or partially in the U.S. state of North Carolina. As of December 31, 2013, the state had a total of of interstate routes and of interstate business routes, all maintained by the North Carolina Department of Transportation (NCDOT).
List of highways in Puerto Rico
Puerto Rico has of Interstate highways. There are three designated Interstate Highways in Puerto Rico. As with Interstate Highways in Alaska and Interstate Highways in Hawaii, these routes do not connect to the rest of the United States Interstate Highway System, but still receive funding in a similar fashion to the Interstates in the contiguous US.
New York State Thruway
The New York State Thruway system is a collection of six individual components across the state of New York that connect the state to four neighboring states (Connecticut, Massachusetts, New Jersey, and Pennsylvania) as well as the Canadian province of Ontario. Together, the highways extend for , making the Thruway system one of the largest toll highway systems in the United States. The longest of the six components is the mainline. Of the 570 miles in the Thruway system, (98.4%) carries at least one Interstate Highway designation. Only three sections of the system are not part of the Interstate Highway System; these are the Garden State Parkway Connector in Rockland County, a portion of the Berkshire Connector between its western terminus at exit 21A on the mainline near Selkirk and where it joins up with Interstate 90 at exit B1 near Castleton-on-Hudson, and a short section of the mainline within exit 24 in Albany that is located between where I-87 departs the roadway and I-90 enters it. They are designated as New York State Route 982L (NY 982L), NY 912M, and NY 915H, respectively, all unsigned reference routes. The speed limit, enforced by the New York State Police, is 65 miles per hour along most of the Thruway.
Interstate 5
Interstate 5 (I-5) is the main Interstate Highway on the West Coast of the United States, running largely parallel to the Pacific coast of the contiguous U.S. from Mexico to Canada. It travels through the states of California, Oregon, and Washington, serving several large cities on the U.S. West Coast, including San Diego, Los Angeles, Sacramento, Portland, and Seattle. It is currently the only continuous Interstate highway to touch both the Mexican border and the Canadian border. Upon crossing the Mexican border at its southern terminus, Interstate 5 continues to Tijuana, Baja California as Mexico Federal Highway 1. Upon crossing the Canadian border at its northern terminus, it continues to Vancouver as British Columbia Highway 99.
List of Interstate Highways
In addition to the 48 contiguous states, Interstate Highways are found in Hawaii, Alaska, and Puerto Rico. The Federal Highway Administration funds four routes in Alaska and three routes in Puerto Rico under the same program as the rest of the Interstate Highway System. However, these routes are not required to meet the same standards as the mainland routes:
Interstate 19
Having a total length of just over , I-19 is the sixth-shortest primary (two-digit) Interstate Highway in the contiguous 48 states, where only I-97, I-86 (western), I-14, I-11, and I-2 are shorter.
Interstate 55
Interstate 55 (I-55) is a major Interstate Highway in the central United States. As with most interstates that end in a five, it is a major cross-country, north-south route, connecting the Gulf of Mexico to the Great Lakes. The highway travels from LaPlace, Louisiana, at I-10 to Chicago at U.S. Route 41 (US 41, Lake Shore Drive), at McCormick Place. The major cities that I-55 connects to includes (from south to north) Jackson, Mississippi; Memphis, Tennessee; and St. Louis.
Interstate 68
Though the National Freeway was designated as US 48, as the completion of the freeway neared, the possibility of the freeway being designated as an Interstate Highway came up. In the 1980s, the project to improve US 50 between Washington, D.C., and Annapolis to Interstate Highway standards had been assigned the designation of I-68. MDSHA, however, later concluded that adding additional route shields to the US 50 freeway would not be helpful to drivers, since about half the freeway already had two route designations (US 50 and US 301) and drivers on the freeway were already familiar with the US 50 designation. This made the designation to be applied to that freeway more flexible, and so in 1989, the American Association of State Highway and Transportation Officials (AASHTO), the organization composed of the various state departments of transportation that decides route numbering in the United States, approved MDSHA's request to renumber the US 50 freeway from I-68 to I-595. That same year, AASHTO approved changing US 48's designation to I-68. This change took effect upon the completion of the last section of the National Freeway, on August 2, 1991.
List of road interchanges in the United States
The following list contains the most notable road interchanges within the United States divided by each state, which are mainly part of the national Interstate Highway System and are all freeways intersecting with each other at a junction.
List of suffixed Interstate Highways
In the United States, there are currently seven "suffixed" Interstate Highways. In addition to the Interstate 35 split into Interstate 35E and Interstate 35W at Dallas-Fort Worth, Texas, a similar split into Interstate 35E and Interstate 35W at Minneapolis-St. Paul, Minnesota exists, as well as Interstate 69C, Interstate 69E and Interstate 69W in South Texas. Interstate 480N in Ohio exists and is designated as such on mile markers but is otherwise unsigned. However, there were once many more, as the three-digit Interstates were not designated until after all major routes were assigned numbers, including some short connections and spurs. (A few of the shortest, including I-190 and I-195, were assigned three-digit numbers almost immediately.) Most were not equal splits like on I-35, but had the main route continue through, and often the suffixed route never returned to its parent. In 1980, AASHTO abolished the majority of suffixes due to confusion, renumbering them as three-digit Interstates, but several that return to their parents were kept. For example, Interstate 15E has since become Interstate 215, but both I-35E/I-35W and I-69 splits still exist, the I-69 splits being recently designated.
Interstate Highway System
While numerous exceptions do exist, there is a general scheme for numbering Interstates. Primary Interstates are assigned one- or two-digit numbers, while shorter routes (such as spurs, loops, and short connecting roads) are assigned three-digit numbers where the last two digits match the parent route (thus, I-294 is a loop that connects at both ends to I-94, while I-787 is a short spur route attached to I-87). In the numbering scheme for the primary routes, east–west highways are assigned even numbers and north–south highways are assigned odd numbers. Odd route numbers increase from west to east, and even-numbered routes increase from south to north (to avoid confusion with the U.S. Highways, which increase from east to west and north to south). This numbering system usually holds true even if the local direction of the route does not match the compass directions. Numbers divisible by five are intended to be major arteries among the primary routes, carrying traffic long distances. Primary north–south Interstates increase in number from I-5 between Canada and Mexico along the West Coast to I‑95 between Canada and Miami, Florida along the East Coast. Major west–east arterial Interstates increase in number from I-10 between Santa Monica, California, and Jacksonville, Florida, to I-90 between Seattle, Washington, and Boston, Massachusetts, with two exceptions. There are no I-50 and I-60, as routes with those numbers would likely pass through states that currently have U.S. Highways with the same numbers, which is generally disallowed under highway administration guidelines.
Oklahoma
Transportation in Oklahoma is generated by an anchor system of Interstate Highways, inter-city rail lines, airports, inland ports, and mass transit networks. Situated along an integral point in the United States Interstate network, Oklahoma contains three primary Interstate highways and four auxiliary Interstate Highways. In Oklahoma City, Interstate 35 intersects with Interstate 44 and Interstate 40, forming one of the most important intersections along the United States highway system.
List of road interchanges in the United States
Some of the biggest ones are: Kennedy Interchange (I-64/I-65/I-71) in Louisville, Kentucky; the Marquette Interchange (I-94/I-43/I-794) and the $1.8 billion Zoo Interchange both in Milwaukee, Wisconsin; the Pregerson Interchange (I-110/I-105) in Los Angeles; and the Circle Interchange (I-90/I-94/I-290) in Chicago.
Transportation in Greater St. Louis
Greater St. Louis contains seven Interstates, including four primary routes (I-44, I-55, I-64, and I-70), and three auxiliary routes (I-270, I-170, and I-255). Greater St. Louis also is linked by four U.S. Highways: US 40, US 50, US 61, and US 67.
Transportation in Dallas
The city of Dallas is at the confluence of a large number of major interstate highways—Interstates 20, 30, 35E, and 45 all run through the city. The city's freeway system, as it has no major geographical inhibitors surrounding it, is set up in the popular hub-and-spoke system, much like a wagon wheel. The center of the system is the downtown freeway loop, made up of Interstate 30 on the south, Interstate 35E on the west, Spur 366 on the north, and Interstate 345 on the east. (Interstate 345 is a short spur of Interstate 45 that connects Interstate 45 with US 75.) The next major freeway loop is the Interstate 635/20 Lyndon B. Johnson loop, and the outermost is the tolled President George Bush Turnpike. Inside these freeway loops are other partially limited-access and parkway-style loops including Loop 12 and Belt Line Road. Another beltway around the city is planned upwards of from downtown in Collin County. Radiating out of downtown as the spokes of the system are Interstates 30, 35E, and 45, US 75, US 175, Spur 366, the tolled Dallas North Tollway, and further out SH 114, US 80 and US 67. Other major highways within the city that do not serve primarily as spokes include SH 183 and Spur 408.
Interstate 270
Interstate 270 is the designation for four Interstate Highways in the United States, all of which are related to Interstate 70:
List of Interstate Highways in Washington
Interstate 90 (I-90) is the longest primary Interstate Highway in Washington, which connects Seattle to Spokane and the Idaho border, measuring , while I-82, connecting the Oregon border city of Umatilla to Elensburg via Yakima, is the shortest at . The longest auxiliary Interstate Highway in Washington is I-405, a bypass of Seattle through the Eastside, at , and the shortest is I-705, a spur into downtown Tacoma, at . One route, I-605, has been proposed over the years to form another Eastside bypass, however there are no plans to construct this fifth auxiliary route.
After passage of the Federal Aid Highway Act of 1956, which formed the Interstate Highway System, the American Association of State Highway Officials had approved I-5 and I-90 across Washington on August 17, 1957. I-82 was approved on October 17, 1957, two months after I-5 and I-90, as part of a addition to the Interstate Highway System.
Interstate Highways in Alaska
Interstates in Alaska follow the numbering system Interstate A-n, where n represents the number of the Interstate. This follows the similar numbering systems for Hawaii and Puerto Rico. The Interstate Highway System was expanded to Alaska in 1976, by the Federal-Aid Highway Act of 1976, which defined the system for Interstates in Alaska and Puerto Rico under Title 23, Chapter 1, Section 103 (c)(1)(B)(ii) of the U.S. Code.
Toll roads in the United States
There are many toll roads in the United States; , toll roads exist in 35 states, with the majority of states without any toll roads being in the West and South. In 2015, there were of toll roads in the country.
Interstate 25
Interstate 25 (I-25) is a major interstate highway in the western United States. It is primarily a north–south highway, serving as the main route through New Mexico, Colorado, and Wyoming. I-25 stretches from Interstate 10 at Las Cruces, New Mexico (approximately north of El Paso, Texas), to Interstate 90 in Buffalo, Wyoming (approximately south of the Montana–Wyoming border). It passes through or near Las Cruces, New Mexico; Truth or Consequences, New Mexico; Socorro, New Mexico; Albuquerque, New Mexico; Santa Fe, New Mexico; Las Vegas, New Mexico; Raton, New Mexico; Pueblo, Colorado; Colorado Springs, Colorado; Denver, Colorado; Fort Collins, Colorado; Cheyenne, Wyoming; and Casper, Wyoming. The I-25 corridor is mainly rural, especially in Wyoming, excluding the Albuquerque, Pueblo, Colorado Springs, and Denver areas.
List of highways in Harris County, Texas
There are currently four interstates located within Harris County. They consist of three major interstates (Interstate 10 (I-10), known as the Katy Freeway and the East Freeway, Interstate 45 (I-45), known as the Gulf Freeway and the North Freeway, and Interstate 69 (I-69), known as the Southwest Freeway and the Eastex Freeway) and one Auxiliary Interstate (Interstate 610 (I-610), known as "The Loop"). There are also three U.S. Routes located in Harris County. These highways consist of U.S. Route 59 (US 59, known as the Southwest Freeway and the Eastex Freeway), U.S. Route 90 (US 90, known as the Crosby Freeway), and U.S. Route 290 (US 290, known as the Northwest Freeway). There are nine state highways, eight spur and loop highways, one park highway, six toll roads (five independent), twenty-two farm to market roads, four bannered U.S. routes, two bannered state routes, and one bannered farm to market road.
Highway systems by country
Many paved highways for vehicles are part of the official National Highway System of the U.S.. Paved highways in the "U.S. Highway" system (for example, U.S. Highway 53) can vary from two lanes wide (one lane each direction), shoulderless, roads with no access control, to multi-lane high-speed controlled-access highway, such as the Interstate Highways. These roads are usually distinguished by being important, but not always the primary, routes that connect populated areas. (Sometimes, the primary route is a State Highway.) Since their inception many decades ago, the construction of "U.S. Highways", and their major improvements, have been paid for 50% with Federal funds, especially from motor fuel taxes, and 50% with State funds from whatever tax resources that the state has. Thus, the system of "U.S. Highways" has always been an equal partnership between the Federal Government and the State governments. This was a plan that changed dramatically with the advent of the Interstate Highway system beginning in the 1950s, but do not forget that the system of "U.S. Highways" continued to be upgraded under the 50%-50% funding. Highways continue to be widened, old bridges continue to be replaces with newer and better ones, and so forth.
List of state routes in Connecticut
Routes are signed state highways and are assigned numbers from 1 to 399 (with the exception of I-684 and I-691). All state, U.S. and Interstate highways are part of the same numbering system. In 1926, the U.S. highway system was implemented. U.S. Routes 1, 5, 6, and 7 were used as designations on several primary state highways, replacing New England routes 1, 2, 3, and 4, respectively. The other New England routes that were not re-designated as U.S. routes became ordinary state highways but kept their number designation, which are used even today (with some realignment). In 1958, Connecticut received approval for the route numbers of its three primary Interstate highways: I-84, I-91, and I-95. State highways with the same number designation as the Interstate highways were renumbered to avoid duplication of route numbers.
Interstate Highway System
The system was proclaimed complete in 1992, but two of the original interstates—I-95 and 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, and thus I-70 remains the only original interstate with a discontinuity.
Interstate 74 in North Carolina
The Intermodal Surface Transportation and Efficiency Act (ISTEA) of 1991 initially authorized the new high priority transportation corridor 5, tentatively known as Interstate 73, to travel from Michigan to South Carolina. Because of several disputes to the routing, a compromise was reached in 1995, by Senator John Warner and Senator Lauch Faircloth, that extended Interstate 74 from its then current eastern terminus of Cincinnati, Ohio to overlap Interstate 73. In Virginia, I-74 would follow I-77 into North Carolina, while I-73 would go east to Roanoke then south along US 220 towards Greensboro. However, when I-73 crossed a border between two states, the federal law authorizing the road required that the two states agree that their sections meet. Originally, both Carolinas selected a route running south from Rockingham, North Carolina. North Carolina had more money to spend on roads, though, and on May 10, 1995, the U.S. Senate Environment and Public Works Committee approved North Carolina's plan for I-73 to run eastward to the coast and enter South Carolina at North Myrtle Beach. Another compromise, between Senator Lauch Faircloth and Senator Strom Thurmond, agreed to have both interstates enter South Carolina: I-73 south of Rockingham and I-74 south of Wilmington. After later amendments and the Transportation Equity Act for the 21st Century of 1996 (TEA-21), on July 25, 1996, AASHTO accepted Interstates 73/74 into the Interstate Highway System within the states of South Carolina, North Carolina, and Virginia.
The portion from south of Steeds north to south of Ulah was completed August 27, 1996, and was the first road marked as I-74 (and I-73). Future signage was also installed north to the Greensboro area. The remainder of of existing and new freeway between Ulah and Candor was also signed as I-73/I-74 along US 220. In 1998, NC 752, a freeway spur of I-77 was renumbered as the segment of completed I-74, from I-77 to US 601. On June 30, 1999, the freeway was extended an additional to US 52, south of Mount Airy. In April 2001, I-74 was overlapped with I-77 from the Virginia state line to exit 101.
List of Interstate Highways in Ohio
As of 2006, out of all the states, Ohio has the fourth-largest Interstate Highway System. Ohio also has the fifth-largest traffic volume and the third-largest quantity of truck traffic. Ohio ranks second in the nation in terms of the number of bridges for its Interstates.
Texas state highway system
The United States Numbered Highways are a nationwide grid of highways, but unlike the Interstate Highway System, there is no minimum design standard for these highways. This is clearly evident as some stretches of the U.S. Highways in Texas are nothing more than a two-lane rural road, while others are urban freeways. Although the U.S. Highways have been replaced for the most part by Interstate Highways for through traffic, the U.S. Highways still serve as important regional connectors. Several notable examples of U.S. Highways that are built to freeway standards include US 75 and US 80 in Dallas, US 59 and US 290 in Houston, and US 90 and US 281 in San Antonio.
List of Interstate Highways in Michigan
The Interstate Highway System covers about in the state and consists of four primary highways and nine auxiliary highways. There are additional 29 business routes associated with the system in Michigan. The longest segment of Interstate Highway in the state is Interstate 75 (I-75) at just under ; the shortest is I-375 at . The length of I-75, the longest highway of any kind in the state, includes the Mackinac Bridge, which is maintained by the MBA, the only section of state highway not under MDOT jurisdiction. The Mackinac Bridge is one of three monumental bridges in the state used by I-75; the others are the Zilwaukee and International bridges. A fourth, the privately owned Ambassador Bridge connects I-75 and I-96 in Detroit to Canada.
Transportation in New York City
A less favored alternative to commuting by rail and boat is the New York region's expressway network, designed by Robert Moses. The city's extensive network of expressways includes four primary Interstate Highways: Interstate 78, Interstate 80, Interstate 87 and Interstate 95. Interstate 78 and Interstate 87, which have, respectively, their eastern and southern termini in the city, as well as Interstate 95 enter the city limits, while Interstate 80's eastern terminus is in Teaneck, New Jersey. I-278 and I-287 each serve as a partial beltway around the city; Interstate 278 in Staten Island, Brooklyn, Queens, and the Bronx, and Interstate 287 in Westchester County, Rockland County, and Northern New Jersey. I-495 begins at the Queens Midtown Tunnel as the Queens-Midtown Expressway, becomes the Horace Harding Expressway between Queens Blvd and the Nassau County limits and finally becomes the Long Island Expressway into the Long Island suburbs. The 'LIE' moniker is commonly used by denizens of the city to describe the entire length of highway.
Interstate Highway System
Typically, lower limits are established in Northeastern and coastal states, while higher speed limits are established in inland states west of the Mississippi River. For example, the maximum speed limit is in northern Maine, varies between from southern Maine to New Jersey, and is in New York City and the District of Columbia. Currently, rural speed limits elsewhere generally range from . Several portions of various highways such as I-10 and I-20 in rural western Texas, I-80 in Nevada between Fernley and Winnemuca (except around Lovelock) and portions of I-15, I-70, I-80, and I-84 in Utah have a speed limit of . Other interstate highways in Idaho, Montana, South Dakota and Wyoming also have the same high speed limits.
Highway systems by country
The term "Highways" in the U.S. even includes major paved roads that serve purposes similar to those of the U.S. Highways or Interstate Highways, but which are completely designed, paid for, and maintained by state or local governments. An example of this is Tennessee Highway 840, which is a long, partially completed "urban bypass" of Nashville, TN that is a multi-lane, controlled-access highway entirely designed and paid for by Tennessee. Much of the traffic on it will eventually come from Interstate 40, completely avoid the big city, and then return to Interstate 40. Incidentally, Tennessee-840 also has connections with Interstate 24 and Interstate 65, where both of the freeway interchanges are already finished, as well as the eastern interchange with Interstate 40.
List of Interstate Highways in Pennsylvania
The list of Interstate Highways in Pennsylvania encompasses 23 Interstate Highways—12 primary routes and 11 auxiliary routes—which exist entirely or partially in the U.S. state of Pennsylvania. In Pennsylvania, most of the Interstate highways are maintained by the Pennsylvania Department of Transportation (PennDOT). Some stretches are also maintained by the Pennsylvania Turnpike Commission, Delaware River Port Authority, the Delaware River Joint Toll Bridge Commission, and 2 short stretches maintained by the New York State Department of Transportation (these being the Delaware River bridge on Interstate 84 and a short stretch of the future Interstate 86 in Bradford County). Interstate highways make up three percent of all roadway lane miles in Pennsylvania and have a combined length of within the state. Twenty-four percent of all vehicle traffic is on the Interstate system.
List of future Interstate Highways
The FAST Act added the US 70 corridor between Garner and Morehead City, North Carolina, to the Interstate system by defining it as, first, High Priority Corridor #82, and subsequently designating it as a future Interstate. The Regional Transportation Alliance expected this corridor to be called Interstate 46 or another suitable designation. At a meeting in La Grange, North Carolina, on March 17, 2016, the Super 70 Corridor Commission recommended that the designation of Interstate 50 be sought for the US 70 Interstate corridor. The rationale for the I-50 numerical selection was cited as a number not in conflict with either an existing Interstate designation or currently applied to a U.S. Highway within North Carolina. This recommendation was forwarded to NCDOT for submission to AASHTO.
List of Interstate Highways in Nebraska
The Interstate Highways in Nebraska are the segments of the national Interstate Highway System that are owned and maintained by the U.S. state of Nebraska, totaling . The longest of these, by far, is Interstate 80 (I-80) at a length just over . After the system was created in 1956, the state department of roads began construction on its Interstates immediately and upon completion of I-80 in 1964 was the first state to complete its mainline Interstate. With the completion of Interstate 129 in 1977, Nebraska completed its contribution to the Interstate Highway System.
Interstate 70
Interstate 70 (I-70) is a major east–west Interstate Highway in the United States that runs from I-15 near Cove Fort, Utah, to I-695 near Baltimore, Maryland. I-70 approximately traces the path of U.S. Route 40 (US 40, the old National Road) east of the Rocky Mountains. West of the Rockies, the route of I-70 was derived from multiple sources. The Interstate runs through or near many major cities, including Denver, Kansas City, St. Louis, Indianapolis, Columbus, Pittsburgh, and Baltimore.
Transportation in the United States
The advent of the automobile signaled the end of railroads as the predominant transportation for people and began an era of mobility in the United States that added greatly to its economic output. The early 20th century Lincoln Highway and other auto trails gave way in the 1920s to an early national highway system making the automobile the preferred mode of travel for most Americans. Interurban rail service declined, followed by trolley cars due in part to the advent of motorized buses and the lack of dedicated rights-of-way but also by deliberate efforts to dismantle urban rail infrastructure (see Great American streetcar scandal). The scarcity of industrial materials during World War II slowed the growth of the automobile, briefly reemphasizing much of the nation's declining rail network. In the 1950s, the United States renewed building a network of high-capacity, high-speed highways to link its vast territory. The most important element is the Interstate Highway system, first commissioned in the 1950s by President Dwight D. Eisenhower and modeled after the Italian autostrada and the German Autobahn system.
Mini Stack
In a 2007 study performed by "Forbes", the Mini Stack ranked number four in the United States in terms of delays with 22 million hours of delays each year. It was behind only Los Angeles' US 101 and I-405 interchange in California, Houston's I-610 and I-10 interchange in Texas, and Chicago's I-90/I-94 and I-290 interchange in Illinois.
Interstate 535
I-535 is the shortest Interstate in both Minnesota and Wisconsin. It also is the only Interstate in the two states with no exit numbers. I-535 in Wisconsin is one of the few instances in the United States of a three-digit Interstate Highway entering a state that its parent two-digit Interstate does not enter. Other examples include Interstate 275 near Cincinnati, Ohio, Interstate 287, and Interstate 129.
Transportation in Georgia (U.S. state)
The state of Georgia has of Interstate Highways within its borders. Georgia's major Interstate Highways are Interstate 16 (I-16), I-20, I-75, I-85, and I-95. Other important interstate highways are I-24 and I-59. I-285 is Atlanta, Georgia's perimeter route and I-575 connects counties in North Georgia to I-75. The Georgia Department of Transportation maintains only 16% of the roads in the state. The other 84% are the responsibility of the counties and cities; 75% of those roads are county roads.
Interstate 495 (Capital Beltway)
Interstate 495 (I-495) is a Interstate Highway that surrounds Washington, D.C., the capital of the United States of America, and its inner suburbs in adjacent Maryland and Virginia. I-495 is widely known as the Capital Beltway, or simply the Beltway, especially when the context of Washington, D.C., is clear. It is the basis of the phrase "inside the Beltway", used when referring to issues dealing with American government and politics. I-95 utilizes the southern and eastern half of the Capital Beltway to circumnavigate Washington, D.C., and is cosigned with I-495 along that portion.
Interstate 5 in Washington
I-5 is the only interstate to traverse the whole state from north to south and is Washington's busiest highway, with an average of 274,000 vehicles traveling on it through Downtown Seattle on a typical day. The segment in Downtown Seattle is also among the widest freeways in the United States, at 13 lanes, and includes a set of express lanes that reverse direction depending on time of the day. I-5 also has three related auxiliary Interstates in the state, I-205, I-405, and I-705, as well as several designated business routes and state routes.
U.S. Route 50
U.S. Route 50 (US 50) is a major east–west route of the U.S. Highway system, stretching just over from West Sacramento, California, to Ocean City, Maryland, on the Atlantic Ocean. Until 1972, when it was replaced by Interstate Highways west of the Sacramento area, it extended (by way of Stockton, the Altamont Pass, and the Bay Bridge) 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 Interstates 70 and 80 and north of Interstates 64 and 40. The route runs through mostly rural desert and mountains in the Western United States, with the section through Nevada known as "The Loneliest Road in America". In the Midwest, US 50 continues through mostly rural areas of farms as well as a few large cities including Kansas City, Missouri; St. Louis, Missouri; and Cincinnati, Ohio. The route continues into the Eastern United States, where it passes through the Appalachian Mountains in West Virginia before heading through Washington, D.C. From there, US 50 continues through Maryland as a high-speed road to Ocean City. Signs at each end give the length as , but the actual distance is slightly less, due to realignments since the former figure was measured. US 50 passes through a total of 12 states; California, Nevada, Utah, Colorado, Kansas, Missouri, Illinois, Indiana, Ohio, West Virginia, Virginia, and Maryland, as well as the District of Columbia.
Interstate 89
I-89 connects smaller cities and rural areas within New Hampshire and Vermont, and maintains two lanes of traffic in each direction throughout the route. Unlike its neighboring Interstates, it does not intersect any even-numbered Interstates along its route. It does, however, parallel (and intersect multiple times with) portions of three U.S. routes: U.S. Route 4 (US 4) from Enfield, New Hampshire, to Hartford, Vermont; US 2 from Montpelier to Colchester, Vermont, and US 7 from Burlington to the Canadian border. US-7 and US-2 overlap each other between Burlington and Colchester.
Transportation in the United States
The Interstate system joined an existing National Highway System (a designation created for the legacy highway network in 1995), comprising 160,000 miles (256,000 kilometers) of roadway, a fraction of the total mileage of roads. The Interstate system serves nearly all major U.S. cities, often through the downtown areas (a point which triggered freeway and expressway revolts in the 1960s and 1970s). The distribution of virtually all goods and services involves Interstate highways at some point. Residents of American cities commonly use urban Interstates to travel to their places of work. The vast majority of long-distance travel, whether for vacation or business, is by the national road network; of these trips, about one-third (by the total number of miles driven in the country in 2003) utilize the Interstate system.
List of gaps in Interstate Highways
In North Carolina, Interstate 26 has a gap in Asheville. This is because not all of the parts in the gap were built to interstate standards. Right now, Interstate 26 is designated as Future I-26, US 19, and US 23. Construction on building this gap to Interstate Standards will begin in 2020. 
Interstate 49 (I-49) currently has four sections: the original alignment from I-10 in Lafayette to I-20 in Shreveport, one from Louisiana Highway 1 near Shreveport to Texarkana; the third section from I-40 near Alma, to US 71 south of Bella Vista, replacing most of I-540 and Arkansas Highway 549; and the last section from Pineville, to Kansas City, Missouri. A short, isolated section of I-49 exists in Bella Vista, Arkansas as Arkansas Highway 549. There is also a short section southeast of Fort Smith that is several miles long. These gaps are expected to be eventually closed.
Speed limits in the United States by jurisdiction
Non-Interstate divided highways (both freeways and expressways) have speed limits of 65 mph in rural areas and up to 60 mph in urban or suburban areas (NOTE: some non-interstate divided highways have gotten speed limit increases in November 2017 such as US Route 169 in the Twin Cities Metropolitan area). Rural two lane State and US highways in Minnesota have a default speed limits of 60 mph although many 55 mph speed limits are still in place after a traffic and engineering study from 2014-2019. County roads have speed limits of up to 55 mph for 2 lanes and 60 for divided sections.
Speed limits in the United States by jurisdiction
Tennessee generally posts its rural interstates at 70 mph. These include all of the state's two-digit Interstates except Interstate 55 and Interstate 26. The only auxiliary interstates in Tennessee with a 70 mph speed limit are Interstate 155 and Interstate 840. 70 mph speed limits are allowed on all other controlled access highways, and are found on controlled-access portions of U.S. 51 and S.R. 22, 111, 386, and 396. In 70 mph zones, the default minimum speed limit is 55. Urban interstates are generally posted at 55 to 65 mph, however, portions of Interstates 24, 40, and 65 and S.R. 386 in Davidson County, as well as I-24 in Clarksville are posted at 70 mph. Four-lane divided highways are posted as high as 65 mph but are sometimes 55 mph. These are often hotbeds for speed camera enforcement leading into a municipality. 55 mph speed limits are allowed on two-lane state maintained roads, but some contain 45 and 50 mph limits, even in rural areas, primarily as a result of local policies. In East Tennessee, most mountain roads leading to North Carolina are poorly posted at 45 mph. Furthermore, two-lane roads such as US 321 and S.R. 91 have the same mountain and road width characteristics when leaving Tennessee into North Carolina or Virginia at 55 mph.
Interstate 65
Interstate 65 (I-65) is a major Interstate Highway in the central United States. As with most interstates that end in a five, it is a major cross-country, north-south route, connecting the Gulf of Mexico to the Great Lakes. Its southern terminus is located at an interchange with I-10 in Mobile, Alabama, and its northern terminus is at an interchange with I-90, U.S. Route 12 (US 12), and U.S. Route 20 (the Dunes Highway) in Gary, Indiana, just southeast of Chicago.
Bypass (road)
In the Interstate Highway System in the United States, bypasses and loops are designated with a three-digit number beginning with an even digit. Note, however, that this pattern is inconsistent enough that, as in greater Des Moines, Iowa the genuine bypass is the main route (in that case, Interstate 35 and Interstate 80, and the loop into downtown Des Moines is Interstate 235; or as in Omaha, Nebraska, where Interstate 480 traverses the downtown area, which is bypassed by Interstate 80 and Interstate 680 and also Interstate 95 which goes through Philadelphia, Pennsylvania and Interstate 295 is the bypass around Philadelphia which goes into New Jersey.
List of Interstate Highways in Michigan
There are also 26 current business routes that connect cities bypassed by the Interstates; 23 are business loops that connect on both ends to their parent highway, and three are business spurs that connect on only one end. I-496 has the Capitol Loop as its connection to the Michigan State Capitol in downtown Lansing. Another six business routes have been designated but are either no longer signed or maintained as state highways.
Federal Aid Highway Act of 1956
Many limited-access toll highways that had been built prior to the Interstate Highway Act were incorporated into the Interstate system (for example, the Ohio Turnpike carries portions of Interstate 76, I-80 and I-90). For major turnpikes in New York, New Jersey, Pennsylvania, Ohio, Indiana, Illinois, Kansas, Oklahoma, Massachusetts, New Hampshire, Maine and West Virginia, tolls continue to be collected, even though the turnpikes have long since been paid for. The money collected is used for highway maintenance, turnpike improvement projects and states' general funds. (That is not the case in Massachusetts, where the state constitution requires the money be used for transportation.) In addition, there are several major toll bridges and toll tunnels included in the interstate highways, including four bridges in the San Francisco Bay Area, ones linking Delaware with New Jersey, New Jersey with New York, New Jersey with Pennsylvania, the Upper and Lower Peninsulas of Michigan and, and between Indiana and Kentucky. Tolls collected on Interstate Highways remain on segments of I-95, I-94, I-90, I-88, I-87, I-80, I-77, I-76, I-64, I-44, I-294, I-355 and several others.
List of business routes of the Interstate Highway System
The Interstate Highway System of the United States, in addition to being a network of freeways, also includes a number of Business Routes assigned by the American Association of State Highway and Transportation Officials. The routes are signed with green shields resembling the Interstate Highway shield. The word is used instead of , and, above the number, where the state name is sometimes included, the word or appears. A business loop has both ends as its "parent", while a business spur has a "dangling end", sometimes running from the end of the Interstate to the downtown area.
List of Interstate Highways
Five route numbers are duplicated in the system, though the corresponding highways are separated by state lines which prevent confusion. The main list that discusses the primary Interstate Highways in the contiguous United States is followed by sections regarding Alaska, Hawaii, and Puerto Rico.
Motel
In the U.S., the Interstate Highway System was bypassing U.S. Highways nationwide. The best-known example was the complete removal of Route 66 from the U.S. highway system in 1985 after it was bypassed (mostly by Interstate 40). U.S. 66 was particularly problematic as the old route number was often moved to the new road as soon as the bypasses were constructed, while Highway Beautification Act restrictions left existing properties with no means to obtain signage on the newly constructed Interstate. Some motels were demolished, converted to private residences, or used as storage space while others have been left to slowly fall apart.
Speed limits in the United States by jurisdiction
Interstate highways have minimum speed limits of 40 mph. There have been talks of 75 mph being enforced on Interstate highways, but a bill allowing the law has yet to be enforced.
List of Interstate Highways in Michigan
Construction of the first expressways in Michigan predates the Interstate Highway System. During World War II, the Michigan State Highway Department (MSHD) built the Willow Run and Detroit Industrial expressways (now part of I-94) to carry workers from Detroit to the defense plants at Willow Run Airport. The state created the Michigan Turnpike Authority (MTA) in 1951, which proposed the construction of a toll freeway to run north–south in the state. The original termini for the Michigan Turnpike were Bridgeport and Rockwood. Interagency politics stalled progress on any proposed turnpikes while MSHD had three freeways under planning or construction.
The Interstate Highway System was authorized by the Federal Aid Highway Act of 1956, and the state had already designed several freeways for its portion of that system. Seizing the opportunity brought by a 1957 state law, the department sold $700 million in bonds (equivalent to $ in 2011) in the late 1950s and early 1960s to finance land purchases and construction of the new freeways. The goal was to connect every city with a population over 50,000 with four-lane freeways that could accommodate rural traffic traveling at . The MSHD delayed numbering these freeways as part of the Interstate Highway System until the federal government had finalized the designations to be assigned to Michigan's freeways. The first highway to be signed as an Interstate in Michigan was I-75, which received signage in late 1959, along a section near the Ohio state line that opened to traffic in October 1957. I-94 was the first of the Interstates to be completed border to border in a US state. In 1974, the state implemented mileage-based exit numbers along the Interstates in Michigan.
Interstate 215
Interstate 215 is the designation for several Interstate Highways in the United States, all of which are related to Interstate 15 (I-15):
Numbered highways in the United States
The Interstate Highway System is a federally funded and administered (but state-maintained) system of freeways that forms the transportation backbone of the U.S., with millions of Americans relying on it for commutes, long-distance travel, and freight transport daily. Interstate highways are all constructed to precise standards, designed to maximize high-speed travel safety and efficiency. Interstate Highways also contain auxiliary routes, which are normally assigned a three-digit route number. All Interstate Highways are part of the National Highway System, a network of highways deemed essential to the defense, economy, and mobility of the country.
Illinois
Major U.S. Interstate highways crossing the state include: Interstate 24 (I-24), I-39, I-41, I-55, I-57, I-64, I-70, I-72, I-74, I-80, I-88, I-90, and I-94.
Interstate 45
At just , I-45 is the shortest of the primary interstates (ending in 0 or 5), and the only primary interstate to be entirely inside of one state.
Route number
In the United States, numbered highways belong to one of three to four systems of numbered routes, depending on the state. There are two national-level route numbering systems, the older United States Numbered Highway System laid out in 1920s, and the newer Interstate Highway System started in the 1950s. Additionally, every state in the U.S. maintains its own set of numbered state highways. Some states have other systems as well, either a system of numbered county highways or secondary state highways. A few cities also have numbered city highways; for example, the city of Charlotte, North Carolina, maintains Charlotte Route 4.
Atlanta
Atlanta has a network of freeways that radiate out from the city, and automobiles are the dominant means of transportation in the region. Three major interstate highways converge in Atlanta: I-20 (east-west), I-75 (northwest-southeast), and I-85 (northeast-southwest). The latter two combine in the middle of the city to form the Downtown Connector (I-75/85), which carries more than 340,000 vehicles per day and is one of the most congested segments of interstate highway in the United States. Atlanta is mostly encircled by Interstate 285, a beltway locally known as "the Perimeter" that has come to mark the boundary between "Inside the Perimeter" (ITP), the city and close-in suburbs, and "Outside the Perimeter" (OTP), the outer suburbs and exurbs. The heavy reliance on automobiles for transportation in Atlanta has resulted in traffic, commute, and air pollution rates that rank among the worst in the country. The City of Atlanta has a higher than average percentage of households without a car. In 2015, 15.2 percent of Atlanta households lacked a car, and increased slightly to 16.4 percent in 2016. The national average is 8.7 percent in 2016. Atlanta averaged 1.31 cars per household in 2016, compared to a national average of 1.8.
List of Interstate Highways in Georgia (U.S. state)
The Interstate Highways in Georgia comprise seven current primary Interstate Highways and eight auxiliary Interstates. In addition, two primary Interstates are currently under proposal, and three auxiliary Interstates were once proposed and than cancelled. Each Interstate has a hidden state route number; for example, Interstate 75 (I-75) is also State Route 401 (SR 401) and Interstate 16 (I-16) is also State Route 404 (SR 404, the Jim Gillis Historic Savannah Parkway). This highway system uses the Georgia Peach Pass for toll lanes.
U.S. Route 1
With the construction of the Interstate Highway System in and after the 1950s, much of US 1 from Houlton to Miami was bypassed by Interstate 95. Between Houlton and Brunswick, Maine, I-95 took a shorter inland route, much of it paralleling US 2 on the alignment proposed for US 1 in 1925. Between Philadelphia and Baltimore, I-95 leaves US 1 to pass through Wilmington. Most notably, I-95 and US 1 follow different corridors between Petersburg, Virginia, and Jacksonville, Florida; while US 1 followed the Fall Line west of the coastal plain, I-95 takes a more direct route through the plain and its swamps. Although some of this part of US 1 was followed by other Interstates—I-85 between Petersburg and Henderson, North Carolina, and I-20 between Camden, South Carolina and Augusta, Georgia—the rest remains an independent route with four lanes in many places. By the late 1970s, most of I-95 had been completed, replacing US 1 as the main corridor of the east coast and relegating most of it to local road status.US 1 has six three-digit auxiliary routes. In numerical order, these are:US 101, despite its number, is not an auxiliary route, but rather considered a primary U.S. Route in its own right as major highway west of the former US 99 on the west coast of the United States.
Interstate 89
Interstate 89 was unique due to one instance of its signage. Between (Vermont) Exits 9 & 10, a sign showing the distance to the next control cities in each direction was completely in metric. While there are many instances of signs being in both miles and kilometers, this was the only case of solely metric in the entire Interstate System. Both signs were replaced in 2010 and show distances in miles only. (Interstate 19 in Arizona used to be the other "only signed in metric" interstate in the U.S., but has been changed over in recent years as the last 2 km have been changed.) Speed limit signs have always been posted in mph.
After Exit 11 in Richmond, I-89 leaves the Green Mountains to enter the Champlain Valley, and a notable shift in the landscape is visible. Here, just outside Burlington, the highway turns northward once again. Also, at this turn is where the only "official" auxiliary highway starts, Interstate 189. A second highway, Interstate 289, was proposed as a beltway through Burlington's northeastern suburbs in the 1980s; amidst controversy, the highway has only been partially completed as Vermont Route 289, a super two roadway. It has yet to directly meet its parent.
U.S. Route 40
Starting at its western terminus in Utah, US 40 crosses a total of 12 states, including Colorado, Kansas, Missouri, Illinois, Indiana, Ohio, West Virginia, Pennsylvania, Maryland, Delaware, and New Jersey. Three former and four current state capitals lie along the route. For much of its route, US 40 runs parallel to or concurrently with several major Interstate Highways: Interstate 70 from Colorado to Washington, Pennsylvania; and again from Hancock, Maryland to Baltimore, Maryland; Interstate 64 in parts of Missouri and Illinois; Interstate 68 along the Maryland Panhandle; and Interstate 95 from Baltimore to New Castle, Delaware.
Environmental Action
In 1956, the United States began constructing the interstate highway system, the largest public works project in history. In rural areas the highways were popular, but by the late 1960s many interstates had destructively begun to penetrate inner cities, destroying neighborhoods, adding pollution, and generating political resistance. Local anti-highway groups sprang up in dozens of locations from Boston to Seattle calling for changes to the Highway Trust Fund, an exclusive source of highway-only dollars from Washington.
Kansas
Kansas is served by two Interstate highways with one beltway, two spur routes, and three bypasses, with over in all. The first section of Interstate in the nation was opened on Interstate 70 (I-70) just west of Topeka on November 14, 1956.
List of Interstate Highways in California
This is a list of Interstates in the U.S. state of California that have existed since the 1964 renumbering. It includes routes that were defined by the California State Legislature but never built, as well as routes that have been entirely relinquished to local governments.
Interstate 90
Interstate 90 (I-90) is an east–west transcontinental freeway, and the longest Interstate Highway in the United States at . Its western terminus is in Seattle, at State Route 519 near T-Mobile Park and CenturyLink Field, and its eastern terminus is in Boston, at Route 1A near Logan International Airport.
List of Interstate Highways in Michigan
The Interstate Highways in Michigan are the segments of the national Dwight D. Eisenhower System of Interstate and Defense Highways that are owned and maintained by the U.S. state of Michigan, totaling about . The longest of these, Interstate 75 (I-75), is also the longest highway of any kind in the state. On a national level, the standards and numbering for the system are handled by the Federal Highway Administration (FHWA) and the American Association of State Highway and Transportation Officials (AASHTO), while the highways in Michigan are maintained by the Michigan Department of Transportation (MDOT) and the Mackinac Bridge Authority (MBA). The Interstates in Michigan have their origins in World War II-era expressways built in the Detroit area. After the system was created in 1956, the state highway department completed its first border-to-border Interstate in 1960. The last highway was completed in 1992, giving Michigan a total of 13 Interstate freeways. The original allotment of mileage to Michigan which would receive federal funding was expanded in 1968, and the United States Congress designated an additional highway in the 1990s that has not yet been built.
Roads and freeways in metropolitan Phoenix
Phoenix freeways are funded primarily by local sales tax dollars rather than federal money, so newer freeways were, and are, given state route designation as opposed to Interstate designation. Primarily due to this, Phoenix is the largest city in the United States to have two Interstate Highways and no three-digit Interstates.
List of Interstate Highways in New York
There are 31 Interstate Highways—9 main routes and 22 auxiliary routes—that exist entirely or partially in the U.S. state of New York. In New York, Interstate Highways are mostly maintained by the New York State Department of Transportation (NYSDOT), with some exceptions. Unlike in some other states, Interstate Highways in New York are not directly referenced by NYSDOT with their number; instead, the letter "I" is suffixed to the number of the route on reference markers and in internal documents. On the surface, there appears to be numerical duplication between several Interstate Highways and state routes—such as I-86 (I-86) and NY 86—but the "I" suffix that is appended to Interstate Highway numbers allows the Interstate Highway and state route to co-exist ("86I" versus "86", respectively).
Transportation in the United States
With the development of the extensive Eisenhower "Interstate Highway System" in the 1950s, both long-distance trips and daily the commute were mostly by private automobile. This network was designed to exacting federal standards in order to receive federal funding. The system, , has a total length of , making it the world's second longest after China's, and the largest public works project in US history.
Transportation in the United States
In addition to the routes of the Interstate system, there are those of the U.S. highway system, not to be confused with the above-mentioned National Highway System. These networks are further supplemented by State Highways, and the local roads of counties, municipal streets, and federal agencies, such as the Bureau of Indian Affairs. There are approximately of roads in the United States, paved and unpaved. State highways are constructed by each state, but frequently maintained by county governments aided by funding from the state, where such counties exist as governing entities (mostly every state except the Northeastern). Counties construct and maintain all remaining roads outside cities, except in private communities. Local, unnumbered roads are often constructed by private contractors to local standards, then maintenance is assumed by the local government.
Geography of South Dakota
South Dakota has a total of 83,609 miles (134,556 km) of highways, roads, and streets, along with 679 miles (1,093 km) of interstate highways. Two major interstates pass through South Dakota: Interstate 90, which runs east and west; and Interstate 29, running north and south in the eastern portion of the state. Also located in the state are the shorter interstates 190 and 229. Several major U.S. highways pass through the state. U.S. routes 12, 14, 16, 18, and 212 travel east and west, while U.S. routes 81, 83, 85 and 281 run north and south.
Railroads have played an important role in South Dakota transportation since the mid-nineteenth century. Some 4,420 miles (7,113 km) of railroad track were built in South Dakota during the late nineteenth and early twentieth centuries, but only 1,839 miles (2,959 km) of railroad are currently operational.
South Dakota's largest commercial airports are located at Sioux Falls and Rapid City.
Transportation in Minnesota
The interstate highways are part of a class of routes known as interregional corridors, which also includes U.S. Routes 2, 8, 10, 14, 52, 53, 61, 63, 169, and 212 and Minnesota State Highways 23, 34, 36, 60, 210, and 371. Interregional corridors represent two percent of the state's highways but account for one-third of all vehicle miles traveled. Less heavily traveled regional corridors include U.S. Routes 12, 59, 71, and 75, and a number of state highways.
Interstate 90 in New York
Interstate 90 (I-90) is a part of the Interstate Highway System that runs from Seattle, Washington, to Boston, Massachusetts. In the U.S. state of New York, I-90 extends from the Pennsylvania state line at Ripley to the Massachusetts state line at Canaan, and is the second-longest highway in the state after NY 17. Although most of the route is part of the tolled New York State Thruway, two non-tolled sections exist along I-90 (the first, situated outside of Buffalo, is included in the Thruway system; the second, situated in the Capital District, is not part of the Thruway system and links Albany and its eastern suburbs). Within New York, I-90 has a complete set of auxiliary Interstates, which means that there are interstates numbered I-190 through I-990 in the state, with no gaps in between. For most of its length in New York, I-90 runs parallel to the former Erie Canal route, New York State Route 5 (NY 5), U.S. Route 20 (US 20) and the CSX railroad mainline that traverses the state.
List of U.S. Highways in Nebraska
The US Highways in Nebraska are the segments of the national United States Numbered Highway System that are owned and maintained by the U.S. State of Nebraska totaling . The longest of these routes is U.S. Route 30 at around . On a national level, the standards and numbering for the system are handled by the American Association of State Highway and Transportation Officials (AASHTO), while the Nebraska Department of Transportation is responsible for their maintenance. Route numbers are not reused between the various highway systems within the state. For example, Interstate 80 is the only route in Nebraska with the number 80.
Speed limits in the United States by jurisdiction
New Mexico has six major freeway facilities, which include three lengthy Interstate routes. Part of US-70 (as a divided highway) between Las Cruces and Alamogordo is the only section of non-Interstate route as well as being the only road in New Mexico that's not a freeway to have the 75 mph limit; as of January 2019, US 285 between Roswell and Vaughn will be raised to 75 mph as well. New Mexico, Nevada (US 95 south of US 93), and Texas are the only three states with 75 mph limits on roads that aren't freeways. There is no statutory requirement for reduced speeds on urban freeways so that, for example at Santa Fe and Las Vegas the speed limit remains 75 mph on I-25. New Mexico, Kansas, North Dakota, Colorado, and Texas are the only states to have a speed limit greater than 70 mph in urban highways. Nonetheless, there are 65 mph limits on freeways in more heavily urbanized areas such as Albuquerque and Las Cruces. Other reduced speed limits do exist, but the lowest speed limit under normal conditions on New Mexico's freeways is 55 mph, which can be found on two sections of Interstate 25: The first section being three miles from the Big I to Gibson Boulevard in Albuquerque, and the second being a short stretch near Raton Pass. These particular stretches of I-25 were originally built as relocations of US-85, whose design and construction predate the interstate highway era. As such, these stretches do not meet modern interstate highway standards, and have closely spaced interchanges, sharp curves, and/or limited sight distances.
Georgia (U.S. state)
Georgia has an extensive interstate highway system including 1,200 miles of interstate highway and 20,000 miles of federal and state highways that facilitate the efficient movement of more than $620 billion of cargo by truck each year. Georgia’s six interstates connect to 80 percent of the U.S. population within a two-day truck drive. More than $14 billion in funding has been approved for new roadway infrastructure.
Interstate 94 in Indiana
In Portage the interstate passes over US 20 and begins to parallel US 20, before having an interchange with SR 249. East of SR 249 the highway leaves Portage and enters Burns Harbor, before passing under SR 149. I-94 has a cloverleaf interchange with US 20, before entering Porter. While passing through Porter, the highway passes over a Norfolk Southern railroad track. After Porter the road enters Chesterton and has an interchange with SR 49. East of SR 49 the freeway leaves Chesterton entering rural Porter County, before entering LaPorte County. The interstate has an interchange with US 421 just south of Michigan City. The road curves to the northeast, bypassing Michigan City to the southeast, having an interchange with US 20. After US 20, I-94 passes over a Chicago South Shore and South Bend Railroad track, before leaving the Michigan City area and entering Michigan. The segment of freeway between US 20 and the Michigan state line has the lowest AADT on I-94 in the state of Indiana, at 37,179 vehicles.
List of auxiliary Interstate Highways
The auxiliary Interstate Highways (also called three-digit Interstate Highways) are a supplemental subset of the freeways within the Interstate Highway System of the United States. Similar to the mainline Interstate Highways, these highways also meet all Interstate Highway Standards (with rare exceptions), they receive the same percentage of federal funding (90%), and they comply with other federal standards.
Numbered highways in the United States
Highways in the United States are split into at least four different types of systems: Interstate Highways, U.S. Highways, state highways, and county highways. Highways are generally organized by a route number or letter. These designations are generally displayed along the route by means of a highway shield. Each system has its own unique shield design that will allow quick identification to which system the route belongs. Below is a list of the different highway shields used throughout the United States.
Interstate 49
Although not part of the original 1957 interstate highway plan, residents of Missouri, Arkansas and Louisiana began campaigning for the highway in 1965 via the "US 71 - I-29 Association." The campaign called for Interstate 29 to be extended south from Kansas City to New Orleans following much of the route along US 71. The plan called for creating a limited access expressway from New Orleans to the Canadian border and on to Winnipeg (via Manitoba Highway 75). The highway is not named Interstate 29 because of interstate naming rules. The rules state that north-south roads are odd numbered and the highways are named in increasing order from west to east. Since there are an Interstate 35 and an Interstate 45 to the west and an Interstate 55 to the east Interstate 49 was chosen for the name.
Illinois
Illinois has a well developed interstate highway system. Illinois has the distinction of having the most primary (two-digit) interstates pass through it among all the 50 states with 13 (with the new addition of Interstate 41 near Wisconsin). Illinois also ranks third among the fifty states with the most interstate mileage, coming in after California and Texas, which are much bigger states in area.
Southern Illinois
Southern Illinois has 4 major interstate freeways that connect with Missouri, Indiana, and Kentucky. Depending on the definition of Little Egypt's boundaries, there are four interstates in the region. I-57 is the main north-south freeway through Southern Illinois. It runs through the center of the area. South of Marion is the western terminus of I-24. It runs southeast, crossing into Paducah, Kentucky near Metropolis. South of its junction with I-24, I-57 bends to the southwest and crosses into Missouri near Illinois' southernmost point by Cairo. I-70 runs east-west from St. Louis to central Indiana. I-64 runs east-west from St. Louis to southern Indiana. It is cosigned with I-57 for a short stretch at Mt. Vernon. I-57 is responsible for much of the growth found around the city of Marion.Bridges and ferries are an important feature in the region, being it is surrounded on three sides by major rivers, the Ohio and Wabash rivers to the east and south, and the Mississippi River to the west.
Indiana:
Interstate Highways in Alaska
The Interstate Highways in Alaska are all owned and maintained by the U.S. state of Alaska. The Alaska Department of Transportation & Public Facilities (DOT&PF) is responsible for the maintenance and operations of the Interstate Highways. The Interstate Highway System in Alaska comprises four highways that cover . The longest of these is A-1, at long, while the shortest route is A-3, at long. All Interstates in Alaska are unsigned and are not generally referred to by their highway numbers.
National Scenic Byway
The most-scenic byways are designated All-American Roads, which must meet two out of the six intrinsic qualities. The designation means they have features that do not exist elsewhere in the United States and are unique and important enough to be tourist destinations unto themselves. As of November 2010, there are 120 National Scenic Byways and 31 All-American Roads, located in 46 states (all except Hawaii, Nebraska, Rhode Island, and Texas).
Interstate 495
Interstate 495 is the designation for several Interstate Highways in the United States, all of which are related to Interstate 95, listed from south to north:
List of Interstate Highways in Wisconsin
The Interstate Highways in Wisconsin comprise five current primary Interstate Highways and three auxiliary Interstates.
List of business routes of the Interstate Highway System
As the main purpose of a Business Interstate is to serve a downtown area, it is typically routed on surface roads. Thus Business Interstates do not meet Interstate Highway standards. AASHTO does, however, apply similar standards as to new U.S. Routes, requiring a new Business Interstate to meet certain design standards. Business Interstates are also sometimes routed onto freeways that were once designated as mainline Interstates themselves (such as Interstate 40 Business in Winston-Salem, North Carolina and Interstate 80 Business in Sacramento, California).
List of highways bypassed by Interstate Highways
This is a list of highways, mostly U.S. Routes, bypassed by Interstate Highways. Unless otherwise specified, designations are as of ca. 1960, at the time the final Interstate plan was adopted. Interstates marked as "later addition" were added after the early 1960s. Locations and corridors are approximate.
List of Interstate Highways in Nevada
The following is a list of Interstate highways in the U.S. state of Nevada. All active mainline Interstates are maintained by the Nevada Department of Transportation, except for a portion of Interstate 215. Interstate business loops are only state-maintained where they overlap with an active State Route or U.S. route.
Interstate 69
Texas continues to actively pursue completing its portion of I-69 by upgrading existing US and state highways along the I-69 corridor to interstate standards. Several portions of the 15 SIUs in Texas are currently being worked on, with active construction in progress on US-59 from SH-99 to Kendleton (SIU 20), and on US-77 between Robstown and Kingsville (SIU 22). Four mainline SIUs outside of Texas are under construction; SIU 3 in Indiana (using $700 million from the 2006 Major Moves deal), SIU 7 and SIU 9 in Tennessee; also a small part of SIU 13 in Arkansas (Monticello Bypass). Portions of these SIUs are open to traffic. Most of the remaining parts of the mainline are in the environmental impact statement (EIS) stages; FHWA has signed records of decision approving the final EIS for SIUs 11, 12, and 13.
United States Numbered Highway System
In general, U.S. Routes do not have a minimum design standard, unlike the later Interstate Highways, and are not usually built to freeway standards. Some stretches of U.S. Routes do meet those standards. Many are designated using the main streets of the cities and towns through which they run. New additions to the system, however, must "substantially meet the current AASHTO design standards". As of 1989, the United States Numbered Highways system has a total length of .
Fresno, California
Fresno is the largest U.S. city not directly linked to an Interstate highway. When the Interstate Highway System was created in the 1950s, the decision was made to build what is now Interstate 5 on the west side of the Central Valley, and thus bypass many of the population centers in the region, instead of upgrading what is now State Route 99. Due to rapidly rising population and traffic in cities along SR 99, as well as the desirability of Federal funding, much discussion has been made to upgrade it to interstate standards and eventually incorporate it into the interstate system, most likely as Interstate 9. Major improvements to signage, lane width, median separation, vertical clearance, and other concerns are currently underway.
List of Interstate Highways in Texas
The Interstate Highways in Texas are all owned and maintained by the U.S. state of Texas. The Texas Department of Transportation (TxDOT) is the agency responsible for the day-to-day maintenance and operations of the Interstate Highways in Texas. The Interstate Highway System in Texas covers and consists of twelve primary routes, seven auxiliary routes and Interstate 35 (I-35) which is split into two branches, I-35E and I-35W, that provide access to both Fort Worth and Dallas. The longest segment of Interstate Highway in Texas is I-10 at ; the shortest is I-110 at .