Taxiway
A taxiway is a path for aircraft at an airport connecting runways with aprons, hangars and other facilities. They have a hard surface such as asphalt or concrete, although smaller general aviation airports sometimes use gravel or grass. Busy airports construct high-speed or rapid-exit taxiways to allow aircraft to leave the runway at higher speeds; this allows the aircraft to vacate the runway quicker, permitting another to land or take off in a shorter interval of time. This is accomplished by making the exiting taxiway longer, thus giving the aircraft more space in which to slow down, before the taxiways' upcoming intersection with another taxiway, another runway, or the ramp/tarmac. Most airports do not have a specific speed limit for taxiing. There is a general rule on safe speed based on obstacles. Operators and aircraft manufacturers might have limits. Typical taxi speeds are 20-30 knots. Normal Centerline A single continuous yellow line, 15 centimetres to 30 centimetres in width. Enhanced Centerline The enhanced taxiway center line marking consists of a parallel line of yellow dashes on either side of the taxiway centerline.
Taxiway centerlines are enhanced for 150 feet before a runway holding position marking. The enhanced taxiway centerline is standard at all FAR Part 139 certified airports in the USA. Taxiway Edge Markings Used to define the edge of the taxiway when the edge does not correspond with the edge of the pavement. Continuous markings consist of a continuous double yellow line, with each line being at least 15 centimetres in width, spaced 15 centimetres apart, they divide the taxiway edge from the shoulder or some other abutting paved surface not intended for use by aircraft. Dashed markings define the edge of a taxiway on a paved surface where the adjoining pavement to the taxiway edge is intended for use by aircraft, e.g. an apron. These markings consist of a broken double yellow line, with each line being at least 15 centimetres in width, spaced 15 centimetres apart; these lines are 15 feet in length with 25 foot gaps. Taxi Shoulder Markings Taxiways, holding bays, aprons are sometimes provided with paved shoulders to prevent blast and water erosion.
Shoulders are not intended for use by aircraft, may be unable to carry the aircraft load. Taxiway shoulder markings are yellow lines perpendicular to the taxiway edge, from taxiway edge to pavement edge, about 3 metres. Surface Painted Taxiway Direction Signs Yellow background with a black inscription, provided when it is not possible to provide taxiway direction signs at intersections, or when necessary to supplement such signs; these markings are located on either side of the taxiway. Surface Painted Location Signs Black background with a yellow inscription and yellow and black border. Where necessary, these markings supplement location signs located alongside the taxiway and assist the pilot in confirming the designation of the taxiway on which the aircraft is located; these markings are located on the right side of the centerline. Geographic Position Markings, they are positioned to the left of the taxiway centerline in the direction of taxiing. Black inscription centered on pink circle with white outer ring.
If the pavement is a light colour the border is white with a black outer ring. Runway Holding Position Markings These show where an aircraft should stop when approaching a runway from a taxiway, they consist of four yellow lines, two solid and two dashed, spaced six or twelve inches apart, extending across the width of the taxiway or runway. The solid lines are always on the side. There are three locations where runway holding position markings are encountered: Runway holding position markings on taxiways. Holding Position Markings for Instrument Landing System These consist of two yellow solid lines spaced two feet apart connected by pairs of solid lines spaced ten feet apart extending across the width of the taxiway. Holding Position Markings for Taxiway/Taxiway Intersections These consist of a single dashed line extending across the width of the taxiway. Surface Painted Holding Position Signs Red background signs with a white inscription to supplement the signs located at the holding position.
The taxiways are given alphanumeric identification. These taxiway IDs are shown on yellow signboards along the taxiways. Airport guidance signs provide information to taxiing aircraft and airport vehicles. Smaller airports may have few or no signs, relying instead on airport charts. There are two classes of signage at airports, with several types of each: Location signs – yellow on black background. Identifies the runway or taxiway the aircraft is on or is entering. Direction/Runway exit signs – black on yellow. Identifies the intersecting taxiways the aircraft is approaching, with an arrow indicating the direction to turn. Stop Bar signs – white on blue background; the designation consists of the letter S followed by designation of the taxiway on which the Stop Bar is positioned. This sign is not standard. Other – many airports use conventional traffic signs such as stop and yield signs throughout the airport. Mandatory instruction signs are white on red, they show entrances to critical areas. Vehicles and aircraft are required to stop at these signs until the control tower gives clearance to proceed.
Runway signs – White text on a red background. These signs identify a runway inte
Highways in the Czech Republic
Highways in the Czech Republic are managed by the state-owned Road and Motorway Directorate of the Czech Republic – ŘSD ČR, established in 1997. The ŘSD manages and maintains 1,250 km of motorways, whose speed limit is of 130 km/h or 80 mph; the present-day national motorway network is due to be of about 2,000 km before 2030. In 2018, for motorcars with a maximum authorized mass of up to 3.5 tonnes, motorways in the Czech Republic are subject to a time-based fee paid with the purchase of a windscreen toll vignette with a validity of either 10 days, 1 month or 1 year. Said, a motorway road sign means that a toll vignette is obligatory. Only sections not subject to vignette are designated with an additional road sign; as of 1 January 2007 a new system of electronic toll aka a distance toll for vehicles with a weight exceeding 12 tons has been introduced for motorways and some roads of the first class cca 200 km. As of 1 January 2010, this applies to vehicles over 3.5 tons. There is an ongoing public discussion on imposition of electronic toll for all vehicles.
First informal plans of a motorway in Czechoslovakia date back to 1935 and was to link Prague through Slovakia with Czechoslovak easternmost territory of Carpathian Ruthenia being Velykyy Bychkiv its end on the Czechoslovak - Romanian border. The definitive route, including a Prague ring motorway, was approved shortly after the Munich Agreement on 4 November 1938 for a planned speed limit of 120 km/h. Nazi authorities made the second Czecho-Slovak Republic a German satellite state, build up a part of the Reichsautobahn Breslau - Vienna as an extraterritorial German motorway with border checkpoints at each motorway exit. However, only a construction of the route within Bohemia and Moravia was initiated, but never finished, it still sporadically appears in some current Czech motorway plans. On 1 December 1938 the Nazi Germany had initiated a construction of so-called Sudetenautobahn in the route Streitau – Eger – Carlsbad – Lobositz – Böhmisch Leipa – Reichenberg – Görlitz; the autobahn has never been finished, but some remnants in the landscape close to Pomezí nad Ohří, Cheb/Eger and Liberec/Reichenberg are still prominent and a not finished part from Svárov via Machnín to Chrastava was used in the construction of the road for motorcars I/35.
After the breakdown of Czechoslovakia following a declaration of independence of the Slovak Republic and of the short-lived Carpatho-Ukraine, a prelude to the German occupation of Bohemia and Moravia on 15 March 1939, a decision to build the motorway only to the Slovak border was adopted. The technical parameters of motorways were adjusted to those of German Reichsautobahn as Czech motorways should be integrated within the German Reichsautobahn network; the project for the first segment Prague - Lužná was ready in January 1939, the construction in Moravia began on 24 January in Chřiby on the Zástřizly - Lužná segment. The construction in Bohemia from Prague on began on 2 May 1939, with switch to right-hand traffic in Bohemia and Moravia gone without a hitch; the motorway should have reached Brno in 1940, but building materials and labour shortage due to an absolute priority of the nazi armament industry delayed the work. The construction in the route of approx. 77 km from Prague towards Brno advanced notably when a prohibition of all civil constructions by German authorities came into force in 1942.
After the Second World War, the completion only of the first and unfinished 77 km of the motorway Prague - Brno up to Humpolec was approved by the Government in November 1945 and was reinaugurated in 1946. The construction sites of the inaugurated construction of the Sudetenautobahn were abandoned, as well as that of the Breslau - Vienna motorway; the latter was, incorporated in some plans as a future connection motorway between Brno and the D35 motorway. Just finishing of some large bridges and a concrete surface on the 77 km of the Prague - Humpolec motorway lacked when the new communist government decided to discontinue the work in early 1950. Only on 8 August 1967 the Government of the Socialist Republic of Czechoslovakia resolved to continue the construction of motorways by adopting a new motorway plan for the whole country and passed a resolution of continuation of the twice interrupted construction of the motorway Prague - Brno and further Brno - Bratislava; the construction was solemnly inaugurated on 8 September 1967.
Due to a change of technical parameters, some bridges finished. The Prague - Brno motorway, initiated on 2 May 1939, reached Brno in 1980, full 40 years after in the beginning scheduled opening; the pace of construction of highways has always been rather slow up to the present days. The first 100 km of highways on the territory of today's Czech Republic were completed in 1975, 500 km in 1985 and 1,000 in 2007. Funding for the construction of highways was radically reduced after the crisis in 2008 due to draconian budget cuts and is gaining momentum rather for various reasons; the motorways in the Czech Republic, Czech: dáln
Brazilian Highway System
The Brazilian Highway System is the highway system of Brazil. As of 2010, the system consists of 2 million kilometers of roads, of which 200,000 km are paved; as it is in the United States, Canada or most countries in Europe, larger/wider highways have higher speed limits than normal urban roads, although minor highways, unpaved highways and sections of major highways running inside urban areas have a lower speed limit in general. The national speed limit for cars driving in non-urban roads is 110 km/h unless otherwise stated, regardless of the road design, weather or daylight. Brazilian Regional highways are named YY-XXX, where YY is the abbreviation of the state where the highway is running in and XXX is a number. Brazilian National highways are named BR-XXX. National highways connect multiple states altogether, are of major importance to the national economy and/or connect Brazil to another country; the meaning of the numbers are: 000-099 - it means. It is an exception to the cases below. 100-199 - it means that the highway runs in a south-north way 200-299 - it means that the highway runs in a west-east way 300-399 - it means that the highway runs in a diagonal way.
Highways with odd numbers run northeast-southwest, while numbers run northwest-southeast. 400-499 - it means that the highway interconnects two major highways. Brazilian highways receive names, but continue to have a YY/BR-XXX name. See highway system of São Paulo for numbering designation for São Paulo state roads used in some other states. In 1953, Adhemar de Barros governor of São Paulo, finished Via Anchieta, linking Santos to São Paulo, Via Anhanguera, linking São Paulo to Campinas; when Juscelino Kubitschek assumed the presidency, he created subsidies to bring multinationals like Volkswagen to Brazil and created thousand of miles of roads, linking distant regions of the country. In 1967, the first stretch of Via Castelo Branco, a 2X3 and 2X2 limited-access highway built at par with standards drawn by FHWA, linking the city of São Paulo to the western region of the São Paulo State, was finished, creating a standard for other highways in the same state. In the same year, the Via Dutra was modernized, between Rio de Janeiro.
The country would reach 200,000 km of paved roads in 2000. Between 1995 and 2005 three major highways were modernised; the Southern and Southeast regions of Brazil are connected by highways, most of them paved. In this region, when they are present are unpaved. Manaus, for example, has no major paved highways connecting it to any other city but Boa Vista in the north. Due to the country's growth and the associated traffic increase, the Government has started the construction and adaptation of main road sections into motorways; the first one to be completed was the so-called Via Dutra, the important highway connecting São Paulo to Rio de Janeiro, finished on the 1975 with a 2X2 setting, but retained some grade crossings. Other roads were built or expanded to dual carriageways, like the Via Fernão Dias, connecting Belo Horizonte to São Paulo; the projects are the link between Brasília and Belo Horizonte, Belo Horizonte and Juiz de Fora, with 200 km, the Rio-Bahia Road System, between Três Rios and Feira de Santana, the important connection between Palmares and Salvador.
The BR-010 is a radial highway that connects the national capital Brasília, to the city of Belém, in the state of Pará. It has the official name of Rodovia Bernardo Sayão, is called Belém-Brasília Highway or as Transbrasiliana Highway, in the stretch between the city of Estreito, in the state of Maranhão, the city of Belém; this is due to the fact that between Brasília and Estreito, the highway has many incomplete and unpaved stretches in the state of Tocantins. Between Brasília and Estreito, the original route of the Belém-Brasília Highway follows the BR-060, the BR-153 and the BR-226 highways, which are paved in this stretch; the BR-010 passes through the Federal District, the states of Goiás, Maranhão and Pará. BR-040 runs radially from near the national capital Brasília, in a northwest-southeast way, to Rio de Janeiro city. BR-040 is the modern way of the so-called "Caminho Novo", opened in the 18th century that linked Ouro Preto, the main center of gold mines of Minas Gerais to the Rio de Janeiro harbor.
In 1861 the road was paved from Petrópolis to Juiz de Fora, becoming the first road paved in Latin America until the 1920s. In 1928, Petrópolis was connected to Rio de Janeiro with a paved road. In the 1930s the route was changed to pass by the new capital of Minas Gerais, Belo Horizonte, although it was unpaved until 1957, when the road was extended to
Oxford English Dictionary
The Oxford English Dictionary is the principal historical dictionary of the English language, published by Oxford University Press. It traces the historical development of the English language, providing a comprehensive resource to scholars and academic researchers, as well as describing usage in its many variations throughout the world; the second edition, comprising 21,728 pages in 20 volumes, was published in 1989. Work began on the dictionary in 1857, but it was only in 1884 that it began to be published in unbound fascicles as work continued on the project, under the name of A New English Dictionary on Historical Principles. In 1895, the title The Oxford English Dictionary was first used unofficially on the covers of the series, in 1928 the full dictionary was republished in ten bound volumes. In 1933, the title The Oxford English Dictionary replaced the former name in all occurrences in its reprinting as twelve volumes with a one-volume supplement. More supplements came over the years until 1989.
Since 2000, compilation of a third edition of the dictionary has been underway half of, complete. The first electronic version of the dictionary was made available in 1988; the online version has been available since 2000, as of April 2014 was receiving over two million hits per month. The third edition of the dictionary will most only appear in electronic form: the Chief Executive of Oxford University Press has stated that it is unlikely that it will be printed; as a historical dictionary, the Oxford English Dictionary explains words by showing their development rather than their present-day usages. Therefore, it shows definitions in the order that the sense of the word began being used, including word meanings which are no longer used; each definition is shown with numerous short usage quotations. This allows the reader to get an approximate sense of the time period in which a particular word has been in use, additional quotations help the reader to ascertain information about how the word is used in context, beyond any explanation that the dictionary editors can provide.
The format of the OED's entries has influenced numerous other historical lexicography projects. The forerunners to the OED, such as the early volumes of the Deutsches Wörterbuch, had provided few quotations from a limited number of sources, whereas the OED editors preferred larger groups of quite short quotations from a wide selection of authors and publications; this influenced volumes of this and other lexicographical works. According to the publishers, it would take a single person 120 years to "key in" the 59 million words of the OED second edition, 60 years to proofread them, 540 megabytes to store them electronically; as of 30 November 2005, the Oxford English Dictionary contained 301,100 main entries. Supplementing the entry headwords, there are 157,000 bold-type derivatives; the dictionary's latest, complete print edition was printed in 20 volumes, comprising 291,500 entries in 21,730 pages. The longest entry in the OED2 was for the verb set, which required 60,000 words to describe some 430 senses.
As entries began to be revised for the OED3 in sequence starting from M, the longest entry became make in 2000 put in 2007 run in 2011. Despite its considerable size, the OED is neither the world's largest nor the earliest exhaustive dictionary of a language. Another earlier large dictionary is the Grimm brothers' dictionary of the German language, begun in 1838 and completed in 1961; the first edition of the Vocabolario degli Accademici della Crusca is the first great dictionary devoted to a modern European language and was published in 1612. The official dictionary of Spanish is the Diccionario de la lengua española, its first edition was published in 1780; the Kangxi dictionary of Chinese was published in 1716. The dictionary began as a Philological Society project of a small group of intellectuals in London: Richard Chenevix Trench, Herbert Coleridge, Frederick Furnivall, who were dissatisfied with the existing English dictionaries; the Society expressed interest in compiling a new dictionary as early as 1844, but it was not until June 1857 that they began by forming an "Unregistered Words Committee" to search for words that were unlisted or poorly defined in current dictionaries.
In November, Trench's report was not a list of unregistered words. The Society realized that the number of unlisted words would be far more than the number of words in the English dictionaries of the 19th century, shifted their idea from covering only words that were not in English diction
Tar
Tar is a dark brown or black viscous liquid of hydrocarbons and free carbon, obtained from a wide variety of organic materials through destructive distillation. Tar can be produced from coal, petroleum, or peat. Production and trade in pine-derived tar was a major contributor in the economies of Northern Europe and Colonial America, its main use was in preserving wooden sailing vessels against rot. The largest user was the Royal Navy of the United Kingdom. Demand for tar declined with the advent of steel ships. Tar-like products can be produced from other forms of organic matter, such as peat. Mineral products resembling tar can be produced from fossil hydrocarbons, such as petroleum. Coal tar is produced from coal as a byproduct of coke production. "Tar" and "pitch" can be used interchangeably. There is a tendency to use "tar" for "pitch" for more solid substances. Both "tar" and "pitch" are applied to viscous forms of asphalt, such as the asphalt found in occurring tar pits. "Rangoon tar" known as "Burmese oil" or "Burmese naphtha", is a form of petroleum.
Oil sands exclusively produced in Alberta, are colloquially referred to as "tar sands" but are in fact composed of bitumen. Note, similar heavy crude grades from Venezuela are not referred to as "tar sands" by Wikipedia or the environmental community. In Northern Europe, the word "tar" refers to a substance, derived from the wood and roots of pine. In earlier times it was used as a water repellent coating for boats and roofs, it is still used as an additive in the flavoring of candy and other foods. Wood tar is microbicidal. Producing tar from wood was known in ancient Greece and has been used in Scandinavia since the Iron Age. For centuries, dating back at least to the 14th century, tar was among Sweden's most important exports. Sweden exported 13,000 barrels of tar in 1615 and 227,000 barrels in the peak year of 1863. Production nearly stopped in the early 20th century, when other chemicals replaced tar, wooden ships were replaced by steel ships. Traditional wooden boats are still sometimes tarred.
The heating of pine wood causes pitch to drip away from the wood and leave behind charcoal. Birch bark is used to make fine tar, known as "Russian oil", suitable for leather protection; the by-products of wood tar are charcoal. When deciduous tree woods are subjected to destructive distillation, the products are methanol and charcoal. Tar kilns are dry distillation ovens used in Scandinavia for producing tar from wood, they were built close from limestone or from more primitive holes in the ground. The bottom is sloped into an outlet hole to allow the tar to pour out; the wood is split into dimensions of a finger, stacked densely, covered tight with dirt and moss. If oxygen can enter, the wood might catch fire, the production would be ruined. On top of this, a fire lit. After a few hours, the tar continues to do so for a few days. Tar was used as tar paper and to seal the hulls of ships and boats. For millennia, wood tar was used to waterproof sails and boats, but today, sails made from inherently waterproof synthetic substances have reduced the demand for tar.
Wood tar is still used to seal traditional wooden boats and the roofs of historical shingle-roofed churches, as well as painting exterior walls of log buildings. Tar is a general disinfectant. Pine tar oil, or wood tar oil, is used for the surface treatment of wooden shingle roofs, boats and tubs and in the medicine and rubber industries. Pine tar has good penetration on the rough wood. An old wood tar oil recipe for the treatment of wood is one-third each genuine wood tar, balsam turpentine, boiled or raw linseed oil or Chinese tung oil. In Finland, wood tar was once considered a panacea reputed to heal "even those cut in twain through their midriff". A Finnish proverb states that "if sauna and tar won't help, the disease is fatal." Wood tar is used in traditional Finnish medicine because of its microbicidal properties. Wood tar is available diluted as tar water, which has numerous uses: As a flavoring for candies and alcohol; as a spice for food, like meat. As a scent for saunas. Tar water is mixed into water, turned into steam in the sauna.
As an anti-dandruff agent in shampoo. As a component of cosmetics. Mixing tar with linseed oil varnish produces tar paint. Tar paint has a translucent brownish hue and can be used to saturate and tone wood and protect it from weather. Tar paint can be toned with various pigments, producing translucent colors and preserving the wood texture. In English and French, "tar" is a substance derived from coal, it was one of the products of gasworks. Tar made from coal or petroleum is considered toxic and carcinogenic because of its high benzene content, though coal tar in low concentrations is used as a topical medicine. Coal and petroleum tar has a pungent odour. Coal tar is listed at number 1999 in the United Nations list of dangerous goods. Bitumen Creosote Pitch Pitch drop experiment Resin Rollins Tars Tarring and feathering Tar Heels Tar pit Tarmac Tar tar ^ "Geotimes – February 2005 – Mummy tar in ancient Egypt". Retrieved January 9, 2006. Details history and uses of "Rangoon Tar"
Highways in Australia
Highways in Australia are high capacity roads managed by state and territory government agencies, though Australia's federal government contributes funding for important links between capital cities and major regional centres. Prior to European settlement, the earliest needs for trade and travel were met by narrow bush tracks, used by tribes of Indigenous Australians; the formal construction of roads began in 1788, after the founding of the colony of New South Wales, a network of three major roads across the colony emerged by the 1820s. Similar road networks were established in the other colonies of Australia. Road construction programs in the early 19th century were underfunded, as they were dependent on government budgets and tolls. Local government authorities known as Road Boards, were therefore established to be responsible for funding and undertaking road construction and maintenance; the early 1900s saw both the widespread use of motorised transportation, the creation of state road authorities in each state, between 1913 and 1926.
These authorities managed each state's road network, with the main arterial roads controlled and maintained by the state, other roads remaining the responsibility of local governments. The federal government became involved in road funding in the 1920s, distributing funding to the states; the depression of the 1930s slowed the funding and development of the major road network until the onset on World War II. Supply roads leading to the north of the country were considered vital, resulting in the construction of Barkly and Eyre Highways; the decades following the war saw substantial improvements to the network, with freeways established in cities, many major highways sealed, development of roads in northern Queensland and Western Australia under the Beef Cattle Roads Grants Acts, interstate routes between Sydney and Melbourne upgraded. In 1974, the federal government assumed responsibility for funding the nations most important road links, between state and territory capitals cities, which were declared National Highways.
Some sections of the 16,000-kilometre-long National Highway system were no more than dirt tracks, while others were four lane dual carriageways. The network was improved, by 1989, all gravel road sections had been sealed. In the following decades, the National Highway system was amended through legislation, was superseded in 2005 by the broader National Land Transport Network, which included connections to major commercial centres, intermodal freight transport facilities; the first route marking system was introduced in the 1950s by the Conference of State Road Authorities, which became the National Association of Australian State Road Authorities and Austroads. National Routes were assigned to significant interstate routes "which, both now and in the future, comprise the more important arteries of road communications throughout Australia in all its aspects". East-west routes were planned to have numbers, increasing from south to north, while north-south routes would have odd numbers, with numbers increasing from east to west.
National Route 1 would be an exception, as a "circumferential route along the coastline of Australia". A state route marking systems was designed to supplement the national system, for inter-regional and urban routes within states; each state could choose their own numbering scheme, as long as National Route and State Route numbers weren't duplicated in the same state, or nearby routes in another state. When the National Highway system was introduced, National Routes along it became National Highway routes with the same numbers, but with distinctive green and gold route markers. During the 1990s, planning began for a new alphanumeric route system. Alphanumeric routes have been introduced in most states and territories in Australia or replacing the previous systems; the earliest needs for trade and travel were met by narrow bush tracks, used by tribes of Indigenous Australian prior to European settlement. The formal construction of roads began after the founding of the colony of New South Wales.
These roads were little more than cleared paths, constructed without grading, drainage systems, road surfaces. There was no system wide planning for roads, with the Surveyor-General's 1788 proposed town plan dismissed as being too ostentatious. By the end of his term in 1822 the colony had a network of three major roads, with the Great Western Road as the most important link, traversing the Blue Mountains from Sydney to Bathurst. Similar road networks were established in the other colonies of Australia. Road construction programs in the early 19th century were underfunded, as they were dependent on government budgets, loans and public subscription; this problem was exacerbated by the huge increase in road usage, due to the Australian gold rushes. Local government authorities were therefore established as authorities responsible for funding and undertaking road construction and maintenance; the increasing amount of motorised transportation in the early 1900s lead to another major increase in traffic levels.
The vehicles required higher standard of roads. State road authorities were established in each state between 1913 and 1926; these authorities managed each state's road network, with the main arterial roads controlled and maintained by the state, other roads remaining the responsibility of local governments. Though legislation
Elevated highway
An elevated highway is a controlled-access highway, raised above grade for its entire length. Elevation is constructed as viaducts a long pier bridge. Technically, the entire highway is a single bridge. Elevated highways are more expensive to build than at-grade highways, are only used where there is some combination of the following on the desired route: difficulty controlling access at grade, for example where it would be disruptive or expensive to eliminate existing crossings at grade at grade construction would not allow for optimal traffic flow, for example due to hilly terrain or existing crossings budget or time to eliminate impeding structures is high, due to acquisition costs, demolition costs, or environmental factors. Other advantages to tunnels are that they do not occupy as much valuable real estate, cause less noise pollution, may cause less long-term environmental damage, protect travellers from surface weather. Below-grade open cuts, which are less costly to maintain, but more expensive to build Early engineering for elevated highways owes much to early elevated railway design, which preceded them.
Elevated highways were first used to: create free traffic flow prevent accidents in busy cities provide some of the first regional connections between nearby cities, in early arterial traffic plansIn the late 19th century and early 20th century and streetcars had frequent accidents where they traversed through population centers. These lead to the first "death avenues", such as 11th Avenue in New York City. Aside from safety and pedestrians crossing trains' paths slowed service. In addition, it became difficult to lay down rail lines, as the construction process was disruptive to normal traffic flow; the existing street grid made it difficult to lay some railroad lines, as the trains required a wide turn radius. This led to the first elevated railways in the late 19th century; the elevated rails, being grade-separated, prevented all pedestrian/vehicle accidents, could allow track bends above existing structures. Their construction could still be disruptive, but was less so, as pier construction to support their elevated structures did not close an entire roadway or long stretches of roadway for an extended period.
However, conversion from at grade railways to elevated did not always take place, many lines continued to be at grade in urban areas well into the 20th century. Concurrently, the increase of automobile and truck traffic early in the 20th century exacerbated many of the safety and free flow issues the railways presented - and in fact, created additional hazards with railways; the increase in traffic meant that for the first time, there was a need to develop new and improved roads between cities. By the 1920s, truck traffic in warehouse and dock areas was high enough that there was frequent congestion and frequent accidents. In 1924, New York City began looking for ways to relieve the problems of the combination of trucks, cars and pedestrians on 11th Avenue, known as Death Avenue before the advent of the car and truck; the mayor, the Manhattan borough president, the police commissioner, the Port Authority, the New York Central Railroad, others worked on various plans to take the railroad and passenger cars off the street, eliminating the major conflicts that led to injury, property damage, traffic jams, delays in service.
The Miller Highway, named after its chief proponent, Borough President Julius Miller, was constructed in sections from 1929 through 1937, became the world's first elevated, controlled access highway. After an interruption for World War II, several extensions were built from 1947 to 1951, under the leadership of urban planner Robert Moses connecting it to his other projects, such as the Henry Hudson Parkway and Brooklyn-Battery Tunnel; the Miller Highway influenced many other subsequent projects, such as Boston's Central Artery and the Pulaski Skyway, Moses' own Gowanus Parkway. At the start the 20th century, New York and New Jersey state officials realized that car traffic on ferries was increasing beyond the ability of the then-current ferry system. Planning for the Holland Tunnel started in 1919, it was constructed from 1922 to 1927; as construction started, New Jersey began planning traffic flows between the tunnel and nearby cities. The legislature passed a bill to extend existing highway Route 1 east through Newark and Jersey City.
Due to local opposition to having new highways disrupt local traffic patterns, the engineers elected to use a viaduct, which became the Pulaski Skyway for the eastern portions of the new route. It opened in 1933
The dictionary definition of tarmacadam at Wiktionary