Misplaced Pages

#624375

114-425: [REDACTED] 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 . In

228-521: A concurrency or overlap. For example, I‑75 and I‑85 share the same roadway in Atlanta ; this 7.4-mile (11.9 km) section, called the Downtown Connector , is labeled both I‑75 and I‑85. Concurrencies between Interstate and US Highway numbers are also allowed in accordance with AASHTO policy, as long as the length of the concurrency is reasonable. In rare instances, two highway designations sharing

342-649: A dual highway ) in 1932 between Cologne and Bonn . It then rapidly constructed the first nationwide system of such roads. The first North American freeways (known as parkways) opened in the New York City area in the 1920s. Britain, heavily influenced by the railways, did not build its first motorway , the Preston By-pass ( M6 ), until 1958. Most technologically advanced nations feature an extensive network of freeways or motorways to provide high-capacity urban travel, or high-speed rural travel, or both. Many have

456-466: A median separates the opposite directions of traffic. This strip may be as simple as a grassy area, or may include a crash barrier such as a " Jersey barrier " or an "Ontario Tall Wall" to prevent head-on collisions . On some freeways, the two carriageways are built on different alignments; this may be done to make use of available corridors in a mountainous area or to provide narrower corridors through dense urban areas . Control of access relates to

570-541: A champion in President Dwight D. Eisenhower, who was influenced by his experiences as a young Army officer crossing the country in the 1919 Motor Transport Corps convoy that drove in part on the Lincoln Highway , the first road across America. He recalled that, "The old convoy had started me thinking about good two-lane highways... the wisdom of broader ribbons across our land." Eisenhower also gained an appreciation of

684-476: A change in the numbering system as a result of a new policy adopted in 1973. Previously, letter-suffixed numbers were used for long spurs off primary routes; for example, western I‑84 was I‑80N, as it went north from I‑80 . The new policy stated, "No new divided numbers (such as I-35W and I-35E , etc.) shall be adopted." The new policy also recommended that existing divided numbers be eliminated as quickly as possible; however, an I-35W and I-35E still exist in

798-635: A civil engineer and the editor of Engineering News-Record , presented his "A Suggested National Highway Policy and Plan" during a gathering of the State Highway Officials and Highway Industries Association at the Congress Hotel in Chicago. In the plan, Mehren proposed a 50,000-mile (80,000 km) system, consisting of five east–west routes and 10 north–south routes. The system would include two percent of all roads and would pass through every state at

912-694: A cloverleaf and trumpet interchange when it opened in 1937, and until the Second World War , boasted the longest illuminated stretch of roadway built. A decade later, the first section of Highway 401 was opened, based on earlier designs. It has since gone on to become the busiest highway in the world. The word freeway was first used in February 1930 by Edward M. Bassett . Bassett argued that roads should be classified into three basic types: highways, parkways , and freeways. In Bassett's zoning and property law -based system, abutting property owners have

1026-683: A cost of $ 25,000 per mile ($ 16,000/km), providing commercial as well as military transport benefits. In 1919, the US Army sent an expedition across the US to determine the difficulties that military vehicles would have on a cross-country trip. Leaving from the Ellipse near the White House on July 7, the Motor Transport Corps convoy needed 62 days to drive 3,200 miles (5,100 km) on the Lincoln Highway to

1140-620: A freeway, specialized pedestrian footbridges or tunnels may also be provided. These structures enable pedestrians and cyclists to cross the freeway at that point without a detour to the nearest road crossing. Access to freeways is typically provided only at grade-separated interchanges , though lower-standard right-in/right-out (left-in/left-out in countries that drive on the left) access can be used for direct connections to side roads. In many cases, sophisticated interchanges allow for smooth, uninterrupted transitions between intersecting freeways and busy arterial roads . However, sometimes it

1254-434: A larger number of guide signs than other roads, and the signs themselves are physically larger. Guide signs are often mounted on overpasses or overhead gantries so that drivers can see where each lane goes. Exit numbers are commonly derived from the exit's distance in miles or kilometers from the start of the freeway. In some areas, there are public rest areas or service areas on freeways, as well as emergency phones on

SECTION 10

#1732837018625

1368-499: A legal status which limits the types of vehicles that can use a highway, as well as a road design that limits the points at which they can access it. Major arterial roads will often have partial access control , meaning that side roads will intersect the main road at grade, instead of using interchanges, but driveways may not connect directly to the main road, and drivers must use intersecting roads to access adjacent land. At arterial junctions with relatively quiet side roads, traffic

1482-518: A milepost system but does not use milepost markers. In Europe and some other countries, motorways typically have similar characteristics such as: Two-lane freeways , often undivided, are sometimes built when traffic volumes are low or right-of-way is limited; they may be designed for easy conversion to one side of a four-lane freeway. (For example, most of the Bert T. Combs Mountain Parkway in eastern Kentucky

1596-447: A motorway is understood as a public road with dual carriageways and at least two lanes each way. All entrances and exits are signposted and all interchanges are grade separated. Central barrier or median present throughout the road. No crossing is permitted, while stopping is permitted only in an emergency. Restricted access to motor vehicles, prohibited to pedestrians, animals, pedal cycles, mopeds, agricultural vehicles. The minimum speed

1710-772: A national-level or even international-level (e.g. European E route ) system of route numbering . There are several international standards that give some definitions of words such as motorways, but there is no formal definition of the English language words such as freeway , motorway , and expressway , or of the equivalent words in other languages such as autoroute , Autobahn , autostrada , autocesta, autoput , that are accepted worldwide—in most cases these words are defined by local statute or design standards or regional international treaties. Descriptions that are widely used include: One green or blue symbol (like [REDACTED] ) appears at motorway entry in countries that follow

1824-589: A number of patterns. The actual pattern is determined by a number of factors including local topology, traffic density, land cost, building costs, type of road, etc. In some jurisdictions feeder/distributor lanes are common, especially for cloverleaf interchanges ; in others, such as the United Kingdom, where the roundabout interchange is common, feeder/distributor lanes are seldom seen. Motorways in Europe typically differ between exits and junctions. An exit leads out of

1938-575: A numbering scheme in which primary Interstates are assigned one- or two-digit numbers, and shorter routes which branch off of longer ones are assigned three-digit numbers where the last two digits match the parent route. The Interstate Highway System is partially financed through the Highway Trust Fund , which itself is funded by a combination of a federal fuel tax and transfers from the Treasury's general fund. Though federal legislation initially banned

2052-594: A park and where intersecting streets crossed over bridges. The Southern State Parkway opened in 1927, while the Long Island Motor Parkway was closed in 1937 and replaced by the Northern State Parkway (opened 1931) and the contiguous Grand Central Parkway (opened 1936). In Germany, construction of the Bonn-Cologne Autobahn began in 1929 and was opened in 1932 by Konrad Adenauer , then

2166-490: A population of greater than 50,000. Eisenhower initially preferred a system consisting of toll roads , but Clay convinced Eisenhower that toll roads were not feasible outside of the highly populated coastal regions. In February 1955, Eisenhower forwarded Clay's proposal to Congress. The bill quickly won approval in the Senate, but House Democrats objected to the use of public bonds as the means to finance construction. Eisenhower and

2280-457: A private venture, was the world's first limited-access roadway. It included many modern features, including banked turns , guard rails and reinforced concrete tarmac . Traffic could turn left between the parkway and connectors, crossing oncoming traffic, so it was not a controlled-access highway (or "freeway" as later defined by the federal government's Manual on Uniform Traffic Control Devices ). Modern controlled-access highways originated in

2394-481: A proposal for an interstate highway system, eventually resulting in the enactment of the Federal-Aid Highway Act of 1956 . Unlike the earlier United States Numbered Highway System, the interstates were designed to be all freeways, with nationally unified standards for construction and signage. While some older freeways were adopted into the system, most of the routes were completely new. In dense urban areas,

SECTION 20

#1732837018625

2508-609: A reduction in deaths in a range from 20% to 50% on those sections. Speed, in Europe, is considered to be one of the main contributory factors to collisions. Some countries, such as France and Switzerland, have achieved a death reduction by a better monitoring of speed. Tools used for monitoring speed might be an increase in traffic density; improved speed enforcement and stricter regulation leading to driver license withdrawal; safety cameras; penalty point; and higher fines. Some other countries use automatic time-over-distance cameras (also known as section controls ) to manage speed. Fatigue

2622-493: A separate roadway or altogether eliminates it. In some parts of the world, notably parts of the US , frontage roads form an integral part of the freeway system. These parallel surface roads provide a transition between high-speed "through" traffic and local traffic. Frequent slip-ramps provide access between the freeway and the frontage road, which in turn provides direct access to local roads and businesses. Except on some two-lane freeways (and very rarely on wider freeways),

2736-510: A similar system of express and local lanes for a maximum width of 21 lanes on a 2-mile (3.2 km) segment between Interstate 805 and California State Route 56 . In Mississauga , Ontario, Highway 401 uses collector-express lanes for a total of 18 lanes through its intersection with Highway 403 / Highway 410 and Highway 427 . These wide freeways may use separate collector and express lanes to separate through traffic from local traffic, or special high-occupancy vehicle lanes , either as

2850-409: A single digit prefixed to the two-digit number of its parent Interstate Highway. Spur routes deviate from their parent and do not return; these are given an odd first digit. Circumferential and radial loop routes return to the parent, and are given an even first digit. Unlike primary Interstates, three-digit Interstates are signed as either east–west or north–south, depending on the general orientation of

2964-411: A special restriction on the innermost lane or a separate roadway, to encourage carpooling . These HOV lanes , or roadways open to all traffic, can be reversible lanes , providing more capacity in the direction of heavy traffic, and reversing direction before traffic switches. Sometimes a collector/distributor road , a shorter version of a local lane, shifts weaving between closely spaced interchanges to

3078-769: A speed limit of 45 mph (70 km/h) because it is a parkway that consists of only one lane per side of the highway. On the other hand, Interstates 15, 80, 84, and 215 in Utah have speed limits as high as 70 mph (115 km/h) within the Wasatch Front , Cedar City , and St. George areas, and I-25 in New Mexico within the Santa Fe and Las Vegas areas along with I-20 in Texas along Odessa and Midland and I-29 in North Dakota along

3192-456: A speed limit of 80 mph (130 km/h). Other Interstates in Idaho, Montana, Oklahoma, South Dakota and Wyoming also have the same high speed limits. In some areas, speed limits on Interstates can be significantly lower in areas where they traverse significantly hazardous areas. The maximum speed limit on I-90 is 50 mph (80 km/h) in downtown Cleveland because of two sharp curves with

3306-467: A suggested limit of 35 mph (55 km/h) in a heavily congested area; I-70 through Wheeling, West Virginia , has a maximum speed limit of 45 mph (70 km/h) through the Wheeling Tunnel and most of downtown Wheeling; and I-68 has a maximum speed limit of 40 mph (65 km/h) through Cumberland, Maryland , because of multiple hazards including sharp curves and narrow lanes through

3420-453: Is a type of highway that has been designed for high-speed vehicular traffic, with all traffic flow—ingress and egress—regulated. Common English terms are freeway , motorway , and expressway . Other similar terms include throughway or thruway and parkway . Some of these may be limited-access highways , although this term can also refer to a class of highways with somewhat less isolation from other traffic. In countries following

3534-599: Is also commonly believed the Interstate Highway System was built for the sole purpose of evacuating cities in the event of nuclear warfare . While military motivations were present, the primary motivations were civilian. The numbering scheme for the Interstate Highway System was developed in 1957 by the American Association of State Highway and Transportation Officials (AASHTO). The association's present numbering policy dates back to August 10, 1973. Within

Interstate Highway System - Misplaced Pages Continue

3648-514: Is considered as a risk factor more specific to monotonous roads such as motorways, although such data are not monitored/recorded in many countries. According to Vinci Autoroutes , one third of accidents in French motorways are due to sleepy driving. Federal Aid Road Act of 1916 The act was introduced by Rep. Dorsey W. Shackleford (D) of Missouri, then amended by Sen. John H. Bankhead (D) of Alabama to conform with model legislation written by

3762-728: Is controlled mainly by two-way stop signs which do not impose significant interruptions on traffic using the main highway. Roundabouts are often used at busier intersections in Europe because they help minimize interruptions in flow, while traffic signals that create greater interference with traffic are still preferred in North America. There may be occasional interchanges with other major arterial roads. Examples include US 23 between SR 15 's eastern terminus and Delaware, Ohio , along with SR 15 between its eastern terminus and I-75 , US 30 , SR 29 / US 33 , and US 35 in western and central Ohio. This type of road

3876-639: Is necessary to exit onto a surface road to transfer from one freeway to another. One example in the United States (notorious for the resulting congestion) is the connection from Interstate 70 to the Pennsylvania Turnpike ( Interstate 70 and Interstate 76 ) through the town of Breezewood, Pennsylvania . Speed limits are generally higher on freeways and are occasionally nonexistent (as on much of Germany's Autobahn network). Because higher speeds reduce decision time, freeways are usually equipped with

3990-450: Is not lower than 50 km/h [31 mph] and the maximum speed is not higher than 130 km/h [81 mph] (except Germany where no speed limit is defined). Motorways are designed to carry heavy traffic at high speed with the lowest possible number of accidents. They are also designed to collect long-distance traffic from other roads, so that conflicts between long-distance traffic and local traffic are avoided. According to

4104-431: Is provided with separate carriageways for the two directions of traffic). Principal arterials may cross through urban areas, serving suburban movements. The traffic is characterized by high speeds and full or partial access control (interchanges or junctions controlled by traffic lights). Other roads leading to a principal arterial are connected to it through side collector roads. In this view, CARE's definition stands that

4218-407: Is sometimes called an expressway . Freeways are usually limited to motor vehicles of a minimum power or weight; signs may prohibit cyclists , pedestrians and equestrians and impose a minimum speed. It is possible for non-motorized traffic to use facilities within the same right-of-way, such as sidewalks constructed along freeway-standard bridges and multi-use paths next to freeways such as

4332-480: Is specially sign-posted as a motorway and is reserved for specific categories of road motor vehicles." Urban motorways are also included in this definition. However, the respective national definitions and the type of roads covered may present slight differences in different EU countries. The first version of modern controlled-access highways evolved during the first half of the 20th century. The Long Island Motor Parkway on Long Island , New York , opened in 1908 as

4446-545: Is the result of several changes, including infrastructure safety and road user behavior (speed or seat belt use), while other matters such as vehicle safety and mobility patterns have an impact that has not been quantified. Motorways are the safest roads by design. While accounting for more than one quarter of all kilometres driven, they contributed only 8% of the total number of European road deaths in 2006. Germany's Federal Highway Research Institute provided International Road Traffic and Accident Database (IRTAD) statistics for

4560-525: Is to have the highway route extend from Tamaulipas , Mexico to Ontario , Canada. The planned I-11 will then bridge the Interstate gap between Phoenix, Arizona and Las Vegas, Nevada , and thus form part of the CANAMEX Corridor (along with I-19 , and portions of I-10 and I-15 ) between Sonora , Mexico and Alberta , Canada. Political opposition from residents canceled many freeway projects around

4674-408: Is two lanes, but work has begun to make all of it four-lane.) These are often called Super two roads. Several such roads are infamous for a high rate of lethal crashes; an outcome because they were designed for short sight distances (sufficient for freeways without oncoming traffic, but insufficient for the years in service as two-lane road with oncoming traffic). An example of such a "Highway to Hell"

Interstate Highway System - Misplaced Pages Continue

4788-533: The American Association of State Highway Officials (AASHO). It provided $ 75 million of federal money in 50–50 matching funds to the states to build up to 6% of their roads statewide over a five-year period. President Woodrow Wilson signed the Federal Aid Road Act on July 11, 1916 at a ceremony attended by members of AASHO, American Automobile Association , and various farm organizations. Wilson

4902-471: The Dallas–Fort Worth metroplex in Texas, and an I-35W and I-35E that run through Minneapolis and Saint Paul , Minnesota, still exist. Additionally, due to Congressional requirements, three sections of I-69 in southern Texas will be divided into I-69W , I-69E , and I-69C (for Central). AASHTO policy allows dual numbering to provide continuity between major control points. This is referred to as

5016-611: The Dartford Crossing (the furthest downstream public crossing of the River Thames ) or where it was not economic to build a motorway alongside the existing road such as the former Cumberland Gap . The A1 is a good example of piece-wise upgrading to motorway standard—as of January 2013, the 639-kilometre-long (397 mi) route had five stretches of motorway (designated as A1(M)), reducing to four stretches in March 2018 with completion of

5130-684: The General Location of National System of Interstate Highways , informally known as the Yellow Book , mapped out what became the Interstate Highway System. Assisting in the planning was Charles Erwin Wilson , who was still head of General Motors when President Eisenhower selected him as Secretary of Defense in January 1953. Some sections of highways that became part of the Interstate Highway System actually began construction earlier. Three states have claimed

5244-603: The Grand Forks area have higher speed limits of 75 mph (120 km/h). As one of the components of the National Highway System , Interstate Highways improve the mobility of military troops to and from airports, seaports, rail terminals, and other military bases. Interstate Highways also connect to other roads that are a part of the Strategic Highway Network , a system of roads identified as critical to

5358-600: The Presidio of San Francisco along the Golden Gate . The convoy suffered many setbacks and problems on the route, such as poor-quality bridges, broken crankshafts, and engines clogged with desert sand. Dwight Eisenhower , then a 28-year-old brevet lieutenant colonel, accompanied the trip "through darkest America with truck and tank," as he later described it. Some roads in the West were a "succession of dust, ruts, pits, and holes." As

5472-470: The Reichsautobahn system, the first "national" implementation of modern Germany's Autobahn network, as a necessary component of a national defense system while he was serving as Supreme Commander of Allied Forces in Europe during World War II . In 1954, Eisenhower appointed General Lucius D. Clay to head a committee charged with proposing an interstate highway system plan. Summing up motivations for

5586-837: The Suncoast Trail along the Suncoast Parkway in Florida . In some US jurisdictions, especially where freeways replace existing roads, non-motorized access on freeways is permitted. Different states of the United States have different laws. Cycling on freeways in Arizona may be prohibited only where there is an alternative route judged equal or better for cycling. Wyoming , the second least densely populated state, allows cycling on all freeways. Oregon allows bicycles except on specific urban freeways in Portland and Medford . In countries such as

5700-498: The US Department of Defense . The system has also been used to facilitate evacuations in the face of hurricanes and other natural disasters. An option for maximizing traffic throughput on a highway is to reverse the flow of traffic on one side of a divider so that all lanes become outbound lanes. This procedure, known as contraflow lane reversal , has been employed several times for hurricane evacuations. After public outcry regarding

5814-461: The US 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

SECTION 50

#1732837018625

5928-531: The United Kingdom new motorways require an Act of Parliament to ensure restricted right of way. Since upgrading an existing road (the "King's Highway") to a full motorway will result in extinguishing the right of access of certain groups such as pedestrians, cyclists and slow-moving traffic, many controlled access roads are not full motorways. In some cases motorways are linked by short stretches of road where alternative rights of way are not practicable such as

6042-424: The United Kingdom , do not distinguish between the two, but others make a distinction; for example, Germany uses the words Kreuz ("cross") or Dreieck ("triangle") for the former and Ausfahrt ("exit") for the latter. In all cases one road crosses the other via a bridge or a tunnel, as opposed to an at-grade crossing . The inter-connecting roads, or slip-roads , which link the two roads, can follow any one of

6156-463: The Vienna convention , the motorway qualification implies that walking and parking are forbidden. A fully controlled-access highway provides an unhindered flow of traffic, with no traffic signals , intersections or property access . They are free of any at-grade crossings with other roads, railways, or pedestrian paths, which are instead carried by overpasses and underpasses . Entrances and exits to

6270-541: 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 US Highways with

6384-472: The concurrency near Breezewood . Traveling in either direction, I-70 traffic must exit the freeway and use a short stretch of US 30 (which includes a number of roadside services) to rejoin I-70. The interchange was not originally built because of a legacy federal funding rule, since relaxed, which restricted the use of federal funds to improve roads financed with tolls. Solutions have been proposed to eliminate

6498-490: The shoulder at regular intervals. In the United States, mileposts usually start at the southern or westernmost point on the freeway (either its terminus or the state line). California , Ohio and Nevada use postmile systems in which the markers indicate mileage through the state's individual counties. However, Nevada and Ohio also use the standard milepost system concurrently with their respective postmile systems. California numbers its exits off its freeways according to

6612-920: The 20th century, the United States Congress began funding roadways through the Federal Aid Road Act of 1916 , and started an effort to construct a national road grid with the passage of the Federal Aid Highway Act of 1921 . In 1926, the United States Numbered Highway System was established, creating the first national road numbering system for cross-country travel. The roads were state-funded and maintained, and there were few national standards for road design. United States Numbered Highways ranged from two-lane country roads to multi-lane freeways. After Dwight D. Eisenhower became president in 1953, his administration developed

6726-497: The A1(M) through North Yorkshire . The most frequent way freeways are laid out is by building them from the ground up after obstructions such as forestry or buildings are cleared away. Sometimes they deplete farmland, but other methods have been developed for economic, social and even environmental reasons. Full freeways are sometimes made by converting at-grade expressways or by replacing at-grade intersections with overpasses; however, in

6840-477: The Bureau of Public Roads, a hand-drawn map of the United States marked with eight superhighway corridors for study. In 1939, Bureau of Public Roads Division of Information chief Herbert S. Fairbank wrote a report called Toll Roads and Free Roads , "the first formal description of what became the Interstate Highway System" and, in 1944, the similarly themed Interregional Highways . The Interstate Highway System gained

6954-529: The House Democrats agreed to instead finance the system through the Highway Trust Fund , which itself would be funded by a gasoline tax. In June 1956, Eisenhower signed the Federal Aid Highway Act of 1956 into law. Under the act, the federal government would pay for 90 percent of the cost of construction of Interstate Highways. Each Interstate Highway was required to be a freeway with at least four lanes and no at-grade crossings. The publication in 1955 of

SECTION 60

#1732837018625

7068-592: The Interstate Highway System amounted to more than 5,000 people annually, with nearly 5,600 fatalities in 2022. The United States government's efforts to construct a national network of highways began on an ad hoc basis with the passage of the Federal Aid Road Act of 1916 , which provided $ 75 million over a five-year period for matching funds to the states for the construction and improvement of highways. The nation's revenue needs associated with World War I prevented any significant implementation of this policy, which expired in 1921. In December 1918, E. J. Mehren,

7182-485: The Interstate Highway program. The Interstates of Alaska and Puerto Rico are numbered sequentially in order of funding without regard to the rules on odd and even numbers. They also carry the prefixes A and PR , respectively. However, these highways are signed according to their local designations, not their Interstate Highway numbers. Furthermore, these routes were neither planned according to nor constructed to

7296-734: The Interstate System". On October 1, 1940, 162 miles (261 km) of the highway now designated I‑70 and I‑76 opened between Irwin and Carlisle . The Commonwealth of Pennsylvania refers to the turnpike as the Granddaddy of the Pikes, a reference to turnpikes . Milestones in the construction of the Interstate Highway System include: The initial cost estimate for the system was $ 25 billion over 12 years; it ended up costing $ 114 billion (equivalent to $ 425 billion in 2006 or $ 618 billion in 2023) and took 35 years. The system

7410-409: The US, any at-grade intersection that ends a freeway often remains an at-grade intersection. Often, when there is a two-lane undivided freeway or expressway, it is converted by constructing a parallel twin corridor, and leaving a median between the two travel directions. The median-side travel lane of the old two-way corridor becomes a passing lane. Other techniques involve building a new carriageway on

7524-476: The United States, allow for limited exceptions: some movable bridges , for instance the Interstate Bridge on Interstate 5 between Oregon and Washington , do require drivers to stop for ship traffic. The crossing of freeways by other routes is typically achieved with grade separation either in the form of underpasses or overpasses . In addition to sidewalks (pavements) attached to roads that cross

7638-703: The United States, including: In addition to cancellations, removals of freeways are planned: The American Association of State Highway and Transportation Officials (AASHTO) has defined a set of standards that all new Interstates must meet unless a waiver from the Federal Highway Administration (FHWA) is obtained. One almost absolute standard is the controlled access nature of the roads. With few exceptions , traffic lights (and cross traffic in general) are limited to toll booths and ramp meters (metered flow control for lane merging during rush hour ). Being freeways , Interstate Highways usually have

7752-693: The Vienna Convention. Exits are marked with another symbol: [REDACTED] . The definitions of "motorway" from the OECD and PIARC are almost identical. In the European Union , for statistical and safety purposes, some distinction might be made between motorway and expressway . For instance a principal arterial might be considered as: Roads serving long distance and mainly interurban movements. Includes motorways (urban or rural) and expressways (road which does not serve properties bordering on it and which

7866-408: The act was signed. Preliminary construction had taken place before the act was signed, and paving started September 26, 1956. The state marked its portion of I-70 as the first project in the United States completed under the provisions of the new Federal-Aid Highway Act of 1956. The Pennsylvania Turnpike could also be considered one of the first Interstate Highways, and is nicknamed "Grandfather of

7980-783: The bridge. The Queen Elizabeth II Bridge / Dartford tunnel at London Orbital is an example of this. London Orbital or the M25 is a motorway surrounding London , but at the last River Thames crossing before its mouth, motorway rules do not apply. (At this crossing the London Orbital is labeled A282 instead.) A few of the more common types of junction are shown below: There are many differences between countries in their geography, economy, traffic growth, highway system size, degree of urbanization and motorization, etc.; all of which need to be taken into consideration when comparisons are made. According to some EU papers, safety progress on motorways

8094-602: The cancellation of the Somerset Freeway . This situation was remedied when the construction of the Pennsylvania Turnpike/Interstate 95 Interchange Project started in 2010 and partially opened on September 22, 2018, which was already enough to fill the gap. However, I-70 remains discontinuous in Pennsylvania , because of the lack of a direct interchange with the Pennsylvania Turnpike at the eastern end of

8208-404: The choice of routing destroyed many well-established neighborhoods, often intentionally as part of a program of " urban renewal ". In the two decades following the 1956 Highway Act, the construction of the freeways displaced one million people, and as a result of the many freeway revolts during this era, several planned Interstates were abandoned or re-routed to avoid urban cores. Construction of

8322-650: The city. In some locations, low speed limits are the result of lawsuits and resident demands; after holding up the completion of I-35E in St. Paul, Minnesota , for nearly 30 years in the courts, residents along the stretch of the freeway from the southern city limit to downtown successfully lobbied for a 45 mph (70 km/h) speed limit in addition to a prohibition on any vehicle weighing more than 9,000 pounds (4,100 kg) gross vehicle weight . I-93 in Franconia Notch State Park in northern New Hampshire has

8436-426: The collection of tolls, some Interstate routes are toll roads , either because they were grandfathered into the system or because subsequent legislation has allowed for tolling of Interstates in some cases. As of 2022, about one quarter of all vehicle miles driven in the country used the Interstate Highway System, which has a total length of 48,890 miles (78,680 km). In 2022 and 2023, the number of fatalities on

8550-492: The common European definition, a motorway is defined as "a road, specially designed and built for motor traffic, which does not serve properties bordering on it, and which: (a) is provided, except at special points or temporarily, with separate carriageways for the two directions of traffic, separated from each other, either by a dividing strip not intended for traffic, or exceptionally by other means; (b) does not cross at level with any road, railway or tramway track, or footpath; (c)

8664-515: The construction of such a system, Clay stated, It was evident we needed better highways. We needed them for safety, to accommodate more automobiles. We needed them for defense purposes, if that should ever be necessary. And we needed them for the economy. Not just as a public works measure, but for future growth. Clay's committee proposed a 10-year, $ 100 billion program ($ 1.13 trillion in 2023), which would build 40,000 miles (64,000 km) of divided highways linking all American cities with

8778-406: The contiguous United States, primary Interstates—also called main line Interstates or two-digit Interstates—are assigned numbers less than 100. 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

8892-426: The country's road system. Prior to its passage (and for several decades afterward), the condition of many roads was deplorable; "They were often little more than trails that were muddy in the rain and dusty the rest of the time. Any long trip by automobile required not only time, patience, and ingenuity, but tire-patching equipment, tools, spare parts, and emergency food and fuel". A growing interest in road improvements

9006-521: The decade of the 1920s, with such projects as the New York parkway system constructed as part of a new national highway system. As automobile traffic increased, planners saw a need for such an interconnected national system to supplement the existing, largely non-freeway, United States Numbered Highways system. By the late 1930s, planning had expanded to a system of new superhighways. In 1938, President Franklin D. Roosevelt gave Thomas MacDonald , chief at

9120-617: The discontinuity, but they have been blocked by local opposition, fearing a loss of business. The Interstate Highway System has been expanded numerous times. The expansions have both created new designations and extended existing designations. For example, I-49 , added to the system in the 1980s as a freeway in Louisiana , was designated as an expansion corridor, and FHWA approved the expanded route north from Lafayette, Louisiana , to Kansas City, Missouri . The freeway exists today as separate completed segments, with segments under construction or in

9234-445: The dissemination of public information. As a result, the 2005 evacuation of New Orleans, Louisiana, prior to Hurricane Katrina ran much more smoothly. According to urban legend , early regulations required that one out of every five miles of the Interstate Highway System must be built straight and flat, so as to be usable by aircraft during times of war. There is no evidence of this rule being included in any Interstate legislation. It

9348-517: The early 1920s in response to the rapidly increasing use of the automobile , the demand for faster movement between cities and as a consequence of improvements in paving processes, techniques and materials. These original high-speed roads were referred to as " dual highways " and have been modernized and are still in use today. Italy was the first country in the world to build controlled-access highways reserved for fast traffic and for motor vehicles only. The Autostrada dei Laghi ("Lakes Motorway"),

9462-426: The federal government, Interstate Highways are owned by the state in which they were built. With few exceptions , all Interstates must meet specific standards , such as having controlled access, physical barriers or median strips between lanes of oncoming traffic, breakdown lanes , avoiding at-grade intersections , no traffic lights , and complying with federal traffic sign specifications. Interstate Highways use

9576-482: The first built in the world, connecting Milan to Lake Como and Lake Maggiore , and now parts of the A8 and A9 motorways, was devised by Piero Puricelli and was inaugurated in 1924. This motorway, called autostrada , contained only one lane in each direction and no interchanges. The Bronx River Parkway was the first road in North America to utilize a median strip to separate the opposing lanes, to be constructed through

9690-412: The first half of the 20th century. Italy was the first country in the world to build controlled-access highways reserved for fast traffic and for motor vehicles only. Italy opened its first autostrada in 1924, A8 , connecting Milan to Varese . Germany began to build its first controlled-access autobahn without speed limits (30 kilometres [19 mi] on what is now A555 , then referred to as

9804-540: The highest speed limits in a given area. Speed limits are determined by individual states. From 1975 to 1986, the maximum speed limit on any highway in the United States was 55 miles per hour (90 km/h), in accordance with federal law. 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,

9918-504: The highway are provided at interchanges by slip roads (ramps), which allow for speed changes between the highway and arterials and collector roads . On the controlled-access highway, opposing directions of travel are generally separated by a median strip or central reservation containing a traffic barrier or grass. Elimination of conflicts with other directions of traffic dramatically improves safety, while increasing traffic capacity and speed. Controlled-access highways evolved during

10032-453: The inefficiency of evacuating from southern Louisiana prior to Hurricane Georges ' landfall in September 1998, government officials looked towards contraflow to improve evacuation times. In Savannah, Georgia , and Charleston, South Carolina , in 1999, lanes of I-16 and I-26 were used in a contraflow configuration in anticipation of Hurricane Floyd with mixed results. In 2004, contraflow

10146-460: The landmark 1916 law expired, new legislation was passed—the Federal Aid Highway Act of 1921 (Phipps Act). This new road construction initiative once again provided for federal matching funds for road construction and improvement, $ 75 million allocated annually. Moreover, this new legislation for the first time sought to target these funds to the construction of a national road grid of interconnected "primary highways", setting up cooperation among

10260-431: 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

10374-449: The mainline. Some auxiliary highways do not follow these guidelines, however. The Interstate Highway System also extends to Alaska , Hawaii , and Puerto Rico , even though they have no direct land connections to any other states or territories. However, their residents still pay federal fuel and tire taxes. The Interstates in Hawaii, all located on the most populous island of Oahu , carry

10488-735: The maximum speed limit is 75 mph (120 km/h) in northern Maine, varies between 50 and 70 mph (80 and 115 km/h) from southern Maine to New Jersey, and is 50 mph (80 km/h) in New York City and the District of Columbia. Currently, rural speed limits elsewhere generally range from 65 to 80 miles per hour (105 to 130 km/h). Several portions of various highways such as I-10 and I-20 in rural western Texas, I-80 in Nevada between Fernley and Winnemucca (except around Lovelock) and portions of I-15 , I-70 , I-80 , and I-84 in Utah have

10602-460: The mayor of Cologne . The German Autobahn became the first nationwide highway system. In Canada , the first precursor with semi-controlled access was The Middle Road between Hamilton and Toronto , which featured a median divider between opposing traffic flow, as well as the nation's first cloverleaf interchange . This highway developed into the Queen Elizabeth Way , which featured

10716-400: The motorway system, whilst a junction is a crossing between motorways or a split/merge of two motorways. The motorway rules end at exits, but not at junctions. However, on some bridges, motorways, without changing appearance, temporarily end between the two exits closest to the bridge (or tunnel), and continue as dual carriageways . This is in order to give slower vehicles a possibility to use

10830-443: The official Interstate Highway standards . On one- or two-digit Interstates, the mile marker numbering almost always begins at the southern or western state line. If an Interstate originates within a state, the numbering begins from the location where the road begins in the south or west. As with all guidelines for Interstate routes, however, numerous exceptions exist. Controlled-access highway A controlled-access highway

10944-561: The original Interstate Highway System was proclaimed complete in 1992, despite deviations from the original 1956 plan and several stretches that did not fully conform with federal standards . The construction of the Interstate Highway System cost approximately $ 114 billion (equivalent to $ 618 billion in 2023). The system has continued to expand and grow as additional federal funding has provided for new routes to be added, and many future Interstate Highways are currently either being planned or under construction. Though heavily funded by

11058-439: The other. Other methods involve constructing a service drive that shortens the long driveways (typically by less than 100 metres (330 ft)). An interchange or a junction is a highway layout that permits traffic from one controlled-access highway to access another and vice versa, whereas an access point is a highway layout where traffic from a distributor or local road can join a controlled-access highway. Some countries, such as

11172-631: The planning phase between them. In 1966, the FHWA designated the entire Interstate Highway System as part of the larger Pan-American Highway System, and at least two proposed Interstate expansions were initiated to help trade with Canada and Mexico spurred by the North American Free Trade Agreement (NAFTA). Long-term plans for I-69 , which currently exists in several separate completed segments (the largest of which are in Indiana and Texas ),

11286-411: The prefix H . There are three one-digit routes in the state ( H-1 , H-2 , and H-3 ) and one auxiliary route ( H-201 ). These Interstates connect several military and naval bases together, as well as the important communities spread across Oahu, and especially within the urban core of Honolulu . Both Alaska and Puerto Rico also have public highways that receive 90 percent of their funding from

11400-506: The public at no charge. Funding was to be distributed to the states based on a formula incorporating each state's geographic area, population, and existing road network. To obtain the funding, states were required to submit project plans, surveys, specifications and estimates to the United States Secretary of Agriculture . The Federal Aid Road Act, as the first federal highway funding law, was instrumental in extending and improving

11514-477: The rate is higher than the risk on urban roads. Speeds are higher on rural roads and autobahns than urban roads, increasing the severity potential of a crash. According to ETSC, German motorways without a speed limit, but with a 130 km/h (81 mph) speed recommendation, are 25% more deadly than motorways with a speed limit. Germany also introduced some 130 km/h (81 mph) speed limits on various motorway sections that were not limited. This generated

11628-643: The rights of light , air and access to highways, but not parkways and freeways; the latter two are distinguished in that the purpose of a parkway is recreation, while the purpose of a freeway is movement. Thus, as originally conceived, a freeway is simply a strip of public land devoted to movement to which abutting property owners do not have rights of light, air or access. Freeways, by definition, have no at-grade intersections with other roads, railroads or multi-use trails . Therefore, no traffic signals are needed and through traffic on freeways does not normally need to stop at traffic signals. Some countries, such as

11742-524: The route, without regard to the route number. For instance, I-190 in Massachusetts is labeled north–south, while I-195 in New Jersey is labeled east–west. Some looped Interstate routes use inner–outer directions instead of compass directions, when the use of compass directions would create ambiguity. Due to the large number of these routes, auxiliary route numbers may be repeated in different states along

11856-417: The same numbers, which is generally disallowed under highway administration guidelines. Several two-digit numbers are shared between unconnected road segments at opposite ends of the country for various reasons. Some such highways are incomplete Interstates (such as I-69 and I-74 ) and some just happen to share route designations (such as I-76 , I-84 , I‑86 , I-87 , and I-88 ). Some of these were due to

11970-503: The same roadway are signed as traveling in opposite directions; one such wrong-way concurrency is found between Wytheville and Fort Chiswell , Virginia, where I‑81 north and I‑77 south are equivalent (with that section of road traveling almost due east), as are I‑81 south and I‑77 north. Auxiliary Interstate Highways are circumferential, radial, or spur highways that principally serve urban areas . These types of Interstate Highways are given three-digit route numbers, which consist of

12084-432: The side of a divided highway that has a lot of private access on one side and sometimes has long driveways on the other side since an easement for widening comes into place, especially in rural areas. When a third carriageway is added, sometimes it can shift a directional carriageway by 20–60 metres (50–200 ft) (or maybe more depending on land availability) as a way to retain private access on one side that favors over

12198-496: The title of first Interstate Highway. Missouri claims that the first three contracts under the new program were signed in Missouri on August 2, 1956. The first contract signed was for upgrading a section of US Route 66 to what is now designated Interstate 44 . On August 13, 1956, work began on US 40 (now I-70) in St. Charles County. Kansas claims that it was the first to start paving after

12312-587: The various state highway planning boards. The Bureau of Public Roads asked the Army to provide a list of roads that it considered necessary for national defense. In 1922, General John J. Pershing , former head of the American Expeditionary Force in Europe during the war, complied by submitting a detailed network of 20,000 miles (32,000 km) of interconnected primary highways—the so-called Pershing Map . A boom in road construction followed throughout

12426-406: The year 2010, comparing overall fatality rates with motorway rates (regardless of traffic intensity): The German autobahn network illustrates the safety trade-offs of controlled access highways. The injury crash rate is very low on autobahns, while 22 people died per 1,000 injury crashes—although autobahns have a lower rate than the 29 deaths per 1,000 injury accidents on conventional rural roads,

12540-443: Was European route E4 from Gävle to Axmartavlan , Sweden. The high rate of crashes with severe personal injuries on that (and similar) roads did not cease until a median crash barrier was installed, transforming the fatal crashes into non-fatal crashes. Otherwise, freeways typically have at least two lanes in each direction; some busy ones can have as many as 16 or more lanes in total. In San Diego, California , Interstate 5 has

12654-431: Was an ardent advocate of good roads and made them a party platform in 1916: "The happiness, comfort and prosperity of rural life, and the development of the city, are alike conserved by the construction of public highways. We, therefore, favor national aid in the construction of post roads and roads for military purposes". Under the act, federal funding was provided for rural post roads on the condition that they be open to

12768-540: Was employed ahead of Hurricane Charley in the Tampa, Florida area and on the Gulf Coast before the landfall of Hurricane Ivan ; however, evacuation times there were no better than previous evacuation operations. Engineers began to apply lessons learned from the analysis of prior contraflow operations, including limiting exits, removing troopers (to keep traffic flowing instead of having drivers stop for directions), and improving

12882-421: 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. I-95 was discontinuous in New Jersey because of

12996-525: Was spurred by farmers who needed roads to take their goods to market, the introduction of Rural Free Delivery by the Postal Service , and the burgeoning popularity of the personal automobile . The 1907 Supreme Court case Wilson v. Shaw also paved the way for passage of the roads act by holding that the Commerce Clause authorized Congress to construct interstate highways. By 1917, every state had

#624375