Eastern Silesia

Posted by admin on September 22, 2018 in Uncategorized |

Eastern Silesia was formerly the Austrian crownland Austrian Silesia, which was occupied by Czechoslovakia after World War I. It had an area of 1,987 sq mi (5,146 km²), with a population of 680,422 in 1900. The capital was Opava. Plans for a plebiscite fell through, and the area was divided between Czechoslovakia and Poland.

The territory was entered by the Czech military on 23 January 1919, after negotiations with Poland broke down.

A final agreement on the border was reached on 28 July 1920.

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Eastern Silesia is remembered today by philatelists, since the plans for the plebiscite included the issuance of special postage stamps. These were stamps of Czechoslovakia and Poland, overprinted with various combinations of “SO” or “S. O.” (Fr. Silesie Orientale), and “1920”. They were in use from February to September 1920. The overprints were produced in considerable numbers; with a few exceptions, the stamps are commonly available today at the minimum price.

The postal history of the territory is quite complicated, with both overprinted and unoverprinted stamps of the contending countries (and Austria) in use at different post offices at different times.

Stefan II (książę Neapolu)

Posted by admin on September 15, 2018 in Uncategorized |

Stefan II (? – zm. 799) był księciem Neapolu w latach 755 – 766.

Panował podczas ważnego okresu przejściowego w historii księstwa. Był tytułowany eminentissimus consul i był przywódcą lokalnej arystokracji, gdy został wyznaczony przez patrycjuszy z Sycylii. Pod koniec jego rządów, ze względu na rozłam w imperium, Neapol praktycznie stał się niezależny. Po jego abdykacji Neapol doświadczał kryzysu aż do wyboru Sergiusza I w 840.

Na początku jego rządów Neapol był wciąż wiernym Grekom księstwem a jego książęta byli wyznaczani przez cesarza. Dlatego w 761 zabronił wstępu papieskiemu wysłannikowi biskupowi Pawłowi, który był przeciwnikiem ikonoklazmu, trzymającego grecki świat. Stefan wspierał ikonoklastów nie mniej niż sam cesarz. W tym czasie Stefan zwracał się do Antiochosa, patrycjusza z Sycylii i swego technicznego zwierzchnika, jako “”naszego pana” i “najznakomitszego patrycjusza i protostrategosa” (763). Jednak do 764 Neapol odrzucił ikonoklazm i Paweł mógł objąć swe biskupstwo.

Po dwunastoletnich pokojowych rządach, podczas których zdobył wielką popularność wśród ludu, miasto nawiedziła dżuma i zdziesiątkowała obywateli i duchowieństwo, włącznie z samym biskupem. Lud obwołał Stefana biskupem. Natychmiast odszukał papieża w Rzymie i został konsekrowany. Chociaż przestał być księciem, to dalej działał jako biskup przez trzydzieści trzy lata, a księstwo przekazał synowi Grzegorzowi II. Miał jeszcze dwóch synów: Cezara, który zmarł w młodości i Teofilakta.

Bianchi Mediolanum

Posted by admin on September 10, 2018 in Uncategorized |

Il Mediolanum 36 è stato un autocarro prodotto dalla Bianchi dal 1934 al 1938.

Fu prodotto dalla Bianchi di Milano su licenza Daimler-Benz sia in versione civile che in versione militare. Il Regio Esercito e la Regia Aeronautica ne acquisirono 200 esemplari più le versioni specializzate autocinema ed autofrigorifero. Fu utilizzato nelle colonie, dove l’autonomia e la facilità di manutenzione lo rendevano adatto alle grandi distanze. Dopo l’armistizio equipaggiò la Wehrmacht

Classificato come autocarro medio, con 3 tonnellate di portata, era a trazione posteriore e poteva trasportare 32 soldati. Il motore diesel MD a 4 cilindri da 57 hp permette un’autonomia di 280 km ed una velocità su strada di 55 km orari. Oltre che nell’allestimento normale, fu adottata la versione autocinema ed autofrigo; in Libia fu utilizzato come piattaforma per un autocannone basato su una mitragliera contraerea francese da 25 mm.

Questa versione, più lunga di 25 cm e più larga di 5 cm, ha la stessa portata ma il peso a vuoto scende a 3,620 tonnellate. Il nuovo motore da 60 hp garantisce una velocità di 67 km orari ed una autonomia di 310 km. La produzione di questa versione migliorata venne annullata in favore del nuovo Bianchi Miles.

Vista frontale

Mediolanum Autocinema in Libia

Sperimentazione con cingoli

Call Cobbs Jr.

Posted by admin on September 3, 2018 in Uncategorized |

Call Cobbs Jr. (also billed as Call Cobbs) (1910 or 1911 – September 21, 1971) was an American jazz pianist, electric harpsichordist, and organist. He is remembered for his work with saxophonist Albert Ayler in the mid- and late 1960s.

Although Cobbs was a veteran musician, Cobbs’s recorded output is fairly small.

In his youth, Cobbs served as companion and guide to the pianist Art Tatum and later accompanied Billie Holiday and replaced Hamp Hawes in the band of Wardell Gray. Cobbs also worked and recorded with the alto saxophonist Johnny Hodges in 1954, when Hodges’ band included John Coltrane. He studied the Schillinger System of musical composition.

He worked most notably with the free jazz saxophonist Albert Ayler from 1964 through 1970, playing piano, rocksichord, and electronic organ in live performances and recordings. He also acted as Ayler’s copyist and musical director. When Ayler’s body was found floating in the East River in New York City on November 25, 1970, Cobbs was called upon to identify the body. (Ayler’s parents also came from Cleveland to identify the body.)

Cobbs was killed by a hit and run driver on September 21, 1971. He died at Jacobi Hospital in the Bronx, New York. He was 60 years old.

With Albert Ayler

With John Coltrane

With Johnny Hodges

With Jack McVea

With Jimmy Rushing

The Four Skillful Brothers

Posted by admin on September 3, 2018 in Uncategorized |

The Four Skillful Brothers” is a German fairy tale collected by the Brothers Grimm, tale number 129. It is Aarne-Thompson type 653.

A poor old father sent his sons out to learn trades. Each one met a man and was persuaded to learn the trade of the man whom he had met. In this manner, the oldest son became a thief, the second an astronomer, the third a huntsman, the fourth a tailor. When they returned, their father put them to the test. He asked his second son how many eggs there were in a nest, high on the tree, and the second son used his telescope to tell him five. Next, the eldest son climbed the tree and stole the eggs without the birds even being aware, and the third son shot all five eggs with one shot. The fourth son sewed both the shattered eggs and the chicks inside them back together, so that when the eldest put the eggs back in the nest, again without the mother bird noticing, they hatched with the only sign being some red thread about their necks.

Not long after, the King’s Daughter was stolen by a Dragon. The brothers set out to rescue her. The astronomer used his telescope to find her, and asked for a ship to reach where she was held captive. The huntsman at first did not dare shoot the dragon, for fear of killing the princess as well. The thief instead stole her away, and they all set out to return to the king. The dragon followed, and this time the huntsman killed him – but when the dragon fell into the ocean, the resulting wave swamped the boat and smashed it to pieces. Finally, the tailor saved them all by sewing the boat back together.

The king did not know which man to give his daughter to, because each one had played an essential part in the rescue. He instead gave them a quarter of the kingdom each, and they agreed that that was better than their quarreling.

MANIAC III

Posted by admin on September 1, 2018 in Uncategorized |

The Maniac III (Mathematical Analyzer Numerical Integrator and Computer Model III) was a second-generation electronic computer (i.e., using solid state electronics rather than vacuum tubes), built in 1961 for use at the Institute for Computer Research at the University of Chicago.

It was designed by Nicholas Metropolis and constructed by the staff of the Institute for Computer Research. Its design was changed to eliminate vacuum tubes, and thus it occupied a very small part of a very large and powerfully air-conditioned room. It used 20,000 diodes and 12,000 transistors, and had 16K 48-bit words of core memory. Its floating multiply time was 71 microseconds, and divide was 81 microseconds.

Its most novel feature was unnormalized significance arithmetic floating point. This allowed users to determine the change in precision of results due to the nature of the computation.

Weighed about 600 pounds (270 kg).

Children’s Overseas Reception Board

Posted by admin on August 28, 2018 in Uncategorized |

The Children’s Overseas Reception Board (CORB) was a British government sponsored organisation. The CORB evacuated 2,664 British children from England, so that they would escape the imminent threat of German invasion and the risk of enemy bombing in World War II. This was during a critical period in British history, between July and September 1940, when the Battle of Britain was raging, and German invasion forces were being amassed across the English Channel.

The children were sent mainly to the four Dominion countries, Canada 1,532 (in nine parties), Australia 577 (three parties), New Zealand 202 (two parties), and South Africa 353 (two parties), but also some to the USA. In the first few months over 211,000 children were registered with the scheme. A further 24,000 children had been approved for sailing in that time and over 1,000 volunteer escorts, including doctors and nurses, enrolled. It was planned as a temporary exile for the children, to return home to their families when conditions permitted.

Even before the Second World War began in September 1939, the British government had prepared for the evacuation of over a million vulnerable people, mainly children, from the towns and cities to safe areas in the countryside away from the risk of enemy bombing. It was widely believed that up to four million people could be killed by enemy attacks on British towns and cities.

When war did eventually break out, the question of sending British children to Commonwealth countries was brought up in Parliament. It was initially rejected on the grounds of creating panic or spreading defeatism. Instead the government decided that the evacuation to rural areas of Britain should continue as it was felt that this was adequate.

Nonetheless, it is estimated that, by the end of 1941, some 14,000 British children had been evacuated overseas by private arrangement, over 6,000 to Canada and some 5,000 to the United States.

They went either to relatives or friends or left as part of private schemes, run by businesses such as Hoover and Kodak, who would evacuate the children of their British employees. At the beginning of the War America was neutral, and had strict immigration laws. This presented a serious obstacle to the U.S.A. accepting any significant number of British refugees.

Initially these British evacuations to America were a private undertaking and not a British Government sponsored or aided evacuation, but this changed later (see below).

In a related American activity, the quasi-governmental “U.S. Committee for the Care of European Children” (USCOM) was established in June 1940. Its purpose, was to try to save mainly Jewish refugee children who came from Continental Europe (as contrasted with those of the CORB from Great Britain), and to evacuate them to America. Images of German bombing raids and European refugees had a major impact on American opinion and this increased when the Germans began bombing the UK. America was neutral until December 1941, which meant that USCOM was still able to operate in Vichy France after May 1940. On the ground in France, the Quaker American Friends Service Committee (AFSC) (the Quakers – see History of the Quakers) worked with the OSE to select children. In a complicated process, several hundred children made it to the United States, though the rescue of many more was ultimately thwarted by the Nazi occupation of southern France. The organisation was strongly supported by First Lady Eleanor Roosevelt. Other organisations and individuals also worked to save Jewish children and send them to the United States.

In 1941 Geoffrey Shakespeare, British Under-Secretary of State for Dominion Affairs, announced that a total of 838 children had been sent under the auspices of the American Committee for the Evacuation of European Children, with the collaboration of the Children’s Overseas Reception Board.

On 10 May 1940, the Germans started their second blitzkrieg that overran the Netherlands, Belgium, and Luxembourg, and threatened France. Neville Chamberlain, resigned immediately as Prime Minister, and Winston Churchill was appointed to head a coalition government. Shortly afterwards the Germans initiated their assault on France, quickly overrunning the northern part of the country and forcing the evacuation of British and French troops from Dunkirk between 27 May and 4 June.

With the fall of France imminent, the children’s evacuation scheme was again presented in the British Parliament, and this time approved.

In Churchill’s newly formed War Cabinet on 17 June, Under-Secretary of State for Dominion Affairs Geoffrey Shakespeare was tasked with implementing the evacuation programme. The same day, negotiations opened with the travel agency Thomas Cook & Son, for the new department to be housed in their London Head Office at 45 Berkeley Street. The British Government would meet the cost of the voyages with contributions taken from parents on a sliding scale, involving a means test.

Although the British Government was now involved, and this scheme was sanctioned by the Cabinet, Churchill and some others were not personally keen on the idea. Queen Elizabeth, wife of King George VI, had made her views clear at the outbreak of war. There was some suggestion that the Queen and her daughters should be evacuated to North America or Canada. To this the Queen replied: ‘The children won’t go without me. I won’t leave the King. And the King will never leave.’ Throughout the Second World War the Queen and her children shared the dangers and difficulties of the rest of the nation.

The new organisation and staff were quickly assembled and the scheme launched. Applications for children would be made through schools throughout the country. They would travel alone and be accompanied by selected teachers or escorts at a ratio of one to every 15 children, in addition to nurses and doctors. They would travel to the port of embarkation and be accommodated in a hostel, where final medical checks were made. In order to embark rapidly; the usual formalities were dispensed with, there would be no passports. Each child was given a luggage label with its C.O.R.B. number and as each child embarked they were given an identity disc, also with its C.O.R.B. number.

At its height the C.O.R.B. employed some 620 staff.

Within two weeks of each other, two ships carrying CORB children ‘Sea Evacuees’ as they were known, were torpedoed by German U-boats.

The first was the Holland America Line’s SS Volendam, whose passengers included 320 children bound for Halifax and New York. She left Liverpool on 29 August with convoy OB-205, consisting of 32 other ships, and including RMS Rangitata, carrying 113 evacuee children bound for Wellington, New Zealand. On 30 August 1940 at about 11.00pm, the convoy was attacked by U-60, firing two torpedoes that hit No. 1 hold and damaged and caused flooding in No.2 hold. The passengers and crew abandoned ship and were rescued by British merchantmen in the convoy, including the Bassethound, the tanker Valldemosa and the Norwegian Olaf Fostenes, together with the British destroyer HMS Sabre. They were taken to Greenock and other west coast ports in Scotland. All 320 children were rescued, the only casualty was the ship’s purser who was drowned. The Volendam did not sink, and was subsequently taken in tow to Scotland for repairs. When she was docked a second unexploded torpedo was found embedded in the bow, if it had exploded she would have probably sunk.

The second incident, which led to the cancellation of the program, occurred 17 September 1940, when the evacuation ship SS City of Benares (Ellerman Lines) carrying 90 children bound for homes in Canada, was torpedoed and sunk. She had left Liverpool on 13 September for Quebec and Montreal. She was in convoy OB-213 with 19 other ships and was 253 miles west-southwest of Rockall, with the Atlantic weather getting worse and the ship sailing slowly. City of Benares was the flagship of the Convoy Commodore, and was leading the convoy. At around 11.45pm she was attacked by U-48 with two torpedoes but they missed. A second torpedo attack just after midnight hit the ship. She was abandoned and sank within 30 minutes. The British destroyer HMS Hurricane picked up 105 survivors and landed them at Greenock. 42 survivors were left adrift in a lifeboat for eight days, until being picked up by HMS Anthony and also landed at Greenock. The ship’s master, the commodore, three staff members, 121 crew members and 134 passengers were lost. 77 of the 90 CORB children died in the sinking. This event brought the evacuation programme to a halt.

The sinking of the City of Benares caused outrage when it was reported on 23 September 1940. The British government protested that children should not have been innocent victims of war. The Americans called it a ‘dastardly act’. The Germans defended the U-boat attack, considering the ship a legitimate military target, and insisted that the British government was to blame for allowing children to travel on such ships in a war zone. The sinking was a public relations disaster for both the CORB programme and the Admiralty. The British public seemed more enraged at the Admiralty than at the Germans. The fact that the escorts were detached, City of Benares was at the head of the convoy, and the convoy was not taking any evasive action all featured prominently in the subsequent inquiry.

Liverpool was the principal port used for evacuation for the North Atlantic routes to Canada and America. Gourock and Greenock in Scotland were also used. Between 21 July and 20 September 1940, 16 voyages were made carrying 2,664 CORB children. In addition there were also privately sponsored voyages. The programme itself was very limited in size; nineteen ships set sail with 3,127 children, the vast majority of whom made it to their temporary foster homes in Canada, Australia, New Zealand, South Africa and the United States.

The following members were appointed to the Advisory Council as announced in Parliament on 26 June 1940.They met at 45 Berkeley Street London W1, Thomas Cook & Sons, Head Office.

The Right Honourable Lord Snell (Chairman), C.B.E., LL.D.Harry Snell, 1st Baron Snell.
Miss Florence Horsbrugh, M.P., Parliamentary Secretary, Ministry of Health.
Mr. James Chuter Ede, M.P., Parliamentary Secretary, Board of Education.
Mr. J. Westwood, M.P., Parliamentary Under-Secretary for Scotland.
Miss Ellen Wilkinson, M.P., Parliamentary Secretary, Ministry of Pensions.
Mr. E. R. Appleton, Organizer of Empire Youth movements.
Major Cyril Bavin, O.B.E., Y.M.C.A.
Reverend John Bennett, Catholic Council of British Overseas Settlement.
The Countess of Bessborough, Chairman of Council, Society for Overseas Settlement of British Women.
Miss, Grace Browning, Girl Guide’s Association.
Mr. Laurence Cadbury, O.B.E., M.A., Chairman, Cadbury Brothers, Limited, an authority on school and welfare problems.
Lieut.-Colonel Culshaw, Salvation Army.
Miss Doggett, O.B.E., League of Empire.
Miss Ellen Evans, Principal, The Glamorgan Training College: also appointed with special reference to Wales.
Captain G. F. Gracey, Save the Children’s Fund.
Mr. Gordon Green, Fairbridge Farm School.
Mr. W. A. F. Hepburn, O.B.E., M.C., LL.D., Director of Education for Ayrshire, also appointed with special reference to Scotland.
Reverend S. W. Hughes, Free Church Council.
Reverend Canon H. E. Hyde, Church of England Council for Empire Settlement.
Miss M. F. Jobson, J.P., Member of Fife Education Authority and County Council; also appointed with special reference to Scotland.
Miss E. A. Jones, M.A., Headmistresses’ Association.
Mr. P. J. Kirkpatrick, Dr. Barnardo’s Homes (Thomas John Barnardo).
Mr. Harold Legat, Boy Scouts’ Association (The Scout Association).
The Right Honourable Sir Ronald Lindsay, G.C.B., G.C.M.G., sometime His Majesty’s Ambassador to Washington.
Mr. W. A. Markham, M.A., Member of Executive National Children’s Home and Orphanage.
Mrs. Norman, Vice-Chairman, Women’s Voluntary Services.
Mrs. E. Parker, Ex-President, National Union of Teachers.
Dr. Donald Paterson, M.D., F.R.C.P., Physician, Great Ormond Street Hospital.
Miss Gladys Pott, C.B.E., ex-Chairman of Executive of Society for Overseas Settlement of British Women.
Mr. Brendan Quin, 1820 Memorial Settlement.
Sir William Reardon Smith, Baronet, an authority on shipping; also appointed with special reference to Wales.
Miss Edith Thompson, C.B.E., Chairman of Executive, Society for the Overseas Settlement of British Women.

A Scottish Advisory Council for CORB was also appointed, which met at 27, St. Andrew’s Square, Edinburgh 2.

The Right Honourable the Lord Provost of Glasgow, P. J. Dollan, Esq., (Chairman).
Mr. Joseph Westwood, M.P., Parliamentary Under-Secretary of State for Scotland. (also attended London HQ meetings)
Mr. A. L. Fletcher, B.A., former Director of Education for the County of Midlothian.
Miss Mary Tweedie, former Headmistress of the Edinburgh Ladies’ College (The Mary Erskine School).
Mrs. McNab Shaw, a member of the Ayr County Council.
Miss Margaret Jobson, J.P., a member of the Fife County Council, and Fife Education Authority, (also attended London HQ meetings).
Mr. W. A. F. Hepburn, O.B.E., M.C., LL.D., Director of Education for Ayrshire, (also attended London HQ meetings).
A representative of the Quarrier’s Homes, Bridge of Weir, who was appointed.

After the disaster of the City of Benares British public opinion was opposed to the continuation of overseas evacuation, fearing further tragedies. Winston Churchill had been opposed to the scheme, so the government announced the cancellation of the CORB program. However, private evacuation efforts continued into late 1941. By September 1940 the Royal Air Force had achieved mastery over the German Luftwaffe in the Battle of Britain and the threat of an imminent German invasion (Operation Sea Lion) had abated.

Although the evacuation scheme had ceased in September 1940, CORB remained active. It was only disbanded, along with the advisory councils, in 1944, by which point the perceived German military threat had diminished.

The German captain of U-48, Kapitänleutnant Heinrich Bleichrodt survived the war, and was held and tried by the Allies on war crimes charges concerning the sinking of the City of Benares. He was accused of sinking the ship with the full knowledge that it had been transporting evacuees. He reaffirmed the German position that there was no way that he or the crew of the submarine could have known who was on board. It was upheld and he was acquitted. However, Bleichrodt refused to apologise to the survivors, despite several crew members of U-48, including the radio operator, expressing their shock and regret once the facts became known.

Располи, Тао

Posted by admin on August 26, 2018 in Uncategorized |

Тао Располи (англ. Tao Ruspoli; род. 7 ноября 1975 года, Бангкок, Таиланд) — итало-американский кинорежиссёр-документалист и музыкант.

Тао Располи — 2-й сын актёра князя Алессандро Русполи и австро-американской актрисы Дебры Бергер[en]. Тао родился в Бангкоке, в Таиланде. Вырос в Риме и Лос-Анджелесе. Окончил Калифорнийский университет в Беркли со степенью бакалавра искусств в области философии.

7 июня 2003 года в городке Вашингтон[en] (штат Виргиния) женился на актрисе Оливии Уайлд. 8 февраля 2011 года пара объявила о разрыве отношений, 3 марта Уайлд подала на развод, который окончательно оформили 29 сентября 2011 года.

Тао — опытный гитарист фламенко и один из основателей Bombay Beach Biennale.

В настоящее время живёт и работает фотографом и режиссёром в городе Ве́нис[en] — пригороде Лос-Анджелеса.

Maratón de Londres

Posted by admin on August 20, 2018 in Uncategorized |

El maratón de Londres es un maratón que se celebra de forma anual en la ciudad de Londres (Reino Unido) desde 1981, normalmente en el mes de abril. Es una de las integrantes del World Marathon Majors, la competición que agrupa los seis grandes maratones (Nueva York, Chicago, Boston, Berlín y Tokio, además de Londres). Desde 2010 el patrocinador de la carrera es Virgin Money, de ahí el nombre Virgin Money London Marathon.

Como todo maratón, el recorrido es de 42,195 km. Su fundador es Chris Brasher, antiguo campeón olímpico de atletismo y famoso deportista, que se inspiró en el maratón de Nueva York.

Cabe destacar la inusual labor de la competición para recaudar dinero con fines caritativos, superior al resto de maratones.​ Según la organización en la edición de 2006 se recaudó la cifra más elevada del mundo con fines benéficos, que ascendió a 41,5 millones de libras esterlinas, de un montante total de 315 millones de libras que se recaudaron con fines benéficos.​

     Récord de la prueba

     Récord de la prueba

Grid plan

Posted by admin on August 14, 2018 in Uncategorized |

The grid plan, grid street plan, or gridiron plan is a type of city plan in which streets run at right angles to each other, forming a grid. The infrastructure cost for regular grid patterns is generally higher than for patterns with discontinuous streets.

Costs for streets depend largely on four variables: street width, street length, block width and pavement width. Two inherent characteristics of the grid plan, frequent intersections and orthogonal geometry, facilitate pedestrian movement. The geometry helps with orientation and wayfinding and its frequent intersections with the choice and directness of route to desired destinations.

In ancient Rome, the grid plan method of land measurement was called centuriation. The grid plan dates from antiquity and originated in multiple cultures; some of the earliest planned cities were built using grid plans.

By 2600 BC, Mohenjo-daro and Harappa, major cities of the Indus Valley Civilization (in what is now Pakistan), were built with blocks divided by a grid of straight streets, running north-south and east-west. Each block was subdivided by small lanes. The cities and monasteries of Gandhara (e.g. Sirkap and Taxila), dating from the 1st millennium BC to the 11th century AD, also had grid-based designs. Islamabad, the capital of Pakistan since 1959, was also founded on the grid-plan of the nearby ruined city of Sirkap.

A workers’ village (2570-2500 BC) at Giza, Egypt, housed a rotating labor force and was laid out in blocks of long galleries separated by streets in a formal grid. Many pyramid-cult cities used a common orientation: a north-south axis from the royal palace and an east-west axis from the temple, meeting at a central plaza where King and God merged and crossed.

Hammurabi king of the Babylonian Empire in the 17th century BC, ordered the rebuilding of Babylon: constructing and restoring temples, city walls, public buildings, and irrigation canals. The streets of Babylon were wide and straight, intersected approximately at right angles, and were paved with bricks and bitumen.

The tradition of grid plans is continuous in China from the 15th century BC onward in the traditional urban planning of various ancient Chinese states. Guidelines put into written form in the Kaogongji during the Spring and Autumn period (770-476 BC) stated: “a capital city should be square on plan. Three gates on each side of the perimeter lead into the nine main streets that crisscross the city and define its grid-pattern. And for its layout the city should have the Royal Court situated in the south, the Marketplace in the north, the Imperial Ancestral Temple in the east and the Altar to the Gods of Land and Grain in the west.”

Teotihuacan, near modern-day Mexico City, is the largest ancient grid-plan site in the Americas. The city’s grid covered 21 square kilometres(8 square miles).

Perhaps the most well-known grid system is that spread through the colonies of the Roman Empire. The archetypal Roman Grid was introduced to Italy first by the Greeks, with such information transferred by way of trade and conquest.

Although the idea of the grid was present in Hellenic societal and city planning, it was not pervasive prior to the 5th century BC. However, it slowly gained primacy through the work of Hippodamus of Miletus, who planned and replanned many Greek cities in accordance with this form. The concept of a grid as the ideal method of town planning had become widely accepted by the time of Alexander the Great. His conquests were a step in the propagation of the grid plan throughout colonies, some as far-flung as Taxila in Pakistan, that would later be mirrored by the expansion of the Roman Empire. The Greek grid had its streets aligned roughly in relation to the cardinal points and generally looked to take advantage of visual cues based on the hilly landscape typical of Greece and Asia Minor. This was probably best exemplified in Priene, in present-day western Turkey, where the orthogonal city grid was based on the cardinal points, on sloping terrain that struck views out[clarification needed] towards a river and the city of Miletus.

The Etruscan people, whose territories in Italy encompassed what would eventually become Rome, founded what is now the city of Marzabotto at the end of the 6th century BC. Its layout was based on Greek Ionic ideas, and it was here that the main east-west and north-south axes of a town (the decumanus maximus and cardo maximus respectively) could first be seen in Italy. According to Stanislawski (1946), the Romans did use grids until the time of the late Republic or early Empire, when they introduced centuriation, a system which they spread around the Mediterranean and into northern Europe later on.

The military expansion of this period facilitated the adoption of the grid form as standard: the Romans established castra (forts or camps) first as military centres; some of them developed into administrative hubs. The Roman grid was similar in form to the Greek version of a grid, but allowed for practical considerations. For example, Roman castra were often sited on flat land, especially close to or on important nodes like river crossings or intersections of trade routes. The dimensions of the castra were often standard, with each of its four walls generally having a length of 660 metres (2,150 ft). Familiarity was the aim of such standardisation: soldiers could be stationed anywhere around the Empire, and orientation would be easy within established towns if they had a standard layout. Each would have the aforementioned decumanus maximus and cardo maximus at its heart, and their intersection would form the forum, around which would be sited important public buildings. Indeed, such was the degree of similarity between towns that Higgins states that soldiers “would be housed at the same address as they moved from castra to castra“. Pompeii has been cited by both Higgins and Laurence[not in citation given] as the best preserved example of the Roman grid.

Outside of the castra, large tracts of land were also divided in accordance with the grid within the walls. These were typically 730 metres (2,400 ft) per side (called centuria), and contained 100 parcels of land (each called heredium). The decumanus maximus and cardo maximus extended from the town gates out towards neighbouring settlements. These were lined up to be as straight as possible, only deviating from their path due to natural obstacles that prevented a direct route.

While the imposition of only one town form regardless of region could be seen as an imposition of imperial authority, there is no doubting the practical reasoning behind the formation of the Roman grid. Under Roman guidance, the grid was designed for efficiency and interchangeability, both facilitated by and aiding the expansion of their empire.

As Japan and the Korean peninsula became politically centralized in the 7th century AD, those societies adopted Chinese grid-planning principles in numerous locations. In Korea, Gyeongju, the capital of Unified Silla, and Sanggyeong, the capital of Balhae, adapted the Tang Dynasty Chinese model. The ancient capitals of Japan, such as Fujiwara-Kyô (AD 694-710), Nara (Heijô-Kyô, AD 710-784), and Kyoto (Heian-Kyô, AD 794-1868) also adapted from Tang’s capital, Chang’an. However, for reasons of defense, the planners of Tokyo eschewed the grid, opting instead for an irregular network of streets surrounding the Edo Castle grounds. In later periods, some parts of Tokyo were grid-planned, but grid plans are generally rare in Japan, and the Japanese addressing system is accordingly based on increasingly fine subdivisions, rather than a grid.

The grid-planning tradition in Asia continued through the beginning of the 20th century, with Sapporo, Japan (est. 1868) following a grid plan under American influence.

New European towns were planned using grids beginning in the 12th century, most prodigiously in the bastides of southern France that were built during the 13th and 14th centuries. Medieval European new towns using grid plans were widespread, ranging from Wales to the Florentine region. Many were built on ancient grids originally established as Roman colonial outposts.

The Roman model was also used in Spanish settlements during the Reconquista of Ferdinand and Isabella. It was subsequently applied in the new cities established during the Spanish colonization of the Americas, after the founding of San Cristóbal de La Laguna (Canary Islands) in 1496. In 1573, King Phillip II of Spain compiled the to guide the construction and administration of colonial communities. The Laws specified a square or rectangular central plaza with eight principal streets running from the plaza’s corners. Hundreds of grid-plan communities throughout the Americas were established according to this pattern, echoing the practices of earlier Indian civilizations.

The baroque capital city of Malta, Valletta, dating back to the 16th Century, was built following a rigid grid plan of uniformly designed houses, dotted with palaces, churches and squares.

The grid plan became popular with the start of the Renaissance in Northern Europe. In 1606, the newly founded city of Mannheim in Germany was the first Renaissance city laid out on the grid plan. Later came the New Town in Edinburgh and almost the entire city centre of Glasgow, and many planned communities and cities in Australia, Canada and the United States.

Derry, constructed in 1613–1618, was the first planned city in Ireland. The central diamond within a walled city with four gates was considered a good design for defence. The grid pattern was widely copied in the colonies of British North America.

In Russia the first planned city was St. Petersburg founded in 1703 by Peter I. Being aware of the modern European construction experience which he examined in the years of his Grand Embassy to Europe, czar ordered Domenico Trezzini to elaborate the first general plan of the city. The project of this architect for Vasilyevsky Island was a typical rectangular grid of streets (originally intended to be canals, like in Amsterdam), with three lengthwise thoroughfares, rectangularly crossed with about 30 crosswise streets.

The shape of street blocks on Vasilyevsky Island is the same, as was later implemented in the Commissioners’ Plan of 1811 for Manhattan: elongated rectangles. The longest side of each block faces the relatively narrow street with a numeric name (in Petersburg they are called Liniya (Line)) while the shortest side faces wide avenues. To denote avenues in Petersburg, a special term prospekt was introduced. Inside the grid of Vasilyevsky Island there are three prospekts, named Bolshoi (Big), Sredniy (Middle) and Maly (Small) while the far ends of each lines cross with the embankments of Bolshaya Neva and Smolenka rivers in the delta of the Neva River.

The peculiarity of ‘lines’ (streets) naming in this grid is that are each side of street has its own number, so one ‘line’ is a side of a street, not the whole street. The numbering is latently zero-based, however the supposed “zero line” has its proper name Kadetskaya liniya, while the opposite side of this street is called the ‘1-st Line’. Next street is named the ‘2-nd Line’ on the eastern side, and the ‘3-rd Line’ on the western side. After the reorganization of house numbering in 1834 and 1858 the even house numbers are used on the odd-numbered lines, and respectively odd house numbers are used for the even-numbered lines. The maximum numbers for ‘lines’ in Petersburg are 28-29th lines.

Later in the middle of the 18th century another grid of rectangular blocks with the numbered streets appeared in the continental part of the city: 13 streets named from the ‘1-st Rota’ up to the ’13-th Rota’, where the companies (German: Rotte, Russian: рота) of the Izmaylovsky Regiment were located.

Many of the earliest cities in the United States, such as Boston, did not start with a grid system. However, even in pre-revolutionary days some cities saw the benefits of such a layout. New Haven Colony, one of the earliest colonies in America, was designed with a tiny 9-square grid at its founding in 1638. On a grander scale, Philadelphia was designed on a rectilinear street grid in 1682: one of the first cities in North America to use a grid system. At the urging of city founder William Penn, surveyor Thomas Holme designed a system of wide streets intersecting at right angles between the Schuylkill River to the west and the Delaware River to the east, including five squares of dedicated parkland. Penn advertised this orderly design as a safeguard against overcrowding, fire, and disease, which plagued European cities. Holme drafted an ideal version of the grid, but alleyways sprouted within and between larger blocks as the city took shape. Arguably the most famous grid plan in history is the plan for New York City formulated in the Commissioners’ Plan of 1811, a visionary proposal by the state legislature of New York for the development of most of Manhattan above Houston Street.

Washington, D.C., the capital of the United States, was planned under French-American architect Pierre Charles L’Enfant. Under the L’Enfant plan, the original District of Columbia was developed using a grid plan that is interrupted by diagonal avenues, most famously Pennsylvania Avenue. These diagonals are often connected by traffic circles, such as Dupont Circle and Washington Circle. As the city grew, the plan was duplicated to cover most of the remainder of the capital. Meanwhile, the core of the city faced disarray and the McMillan Plan, led by Senator James McMillan, was adopted to build a National Mall and a parks system that is still today a jewel of the city.

Often, some of the streets in a grid are numbered (First, Second, etc.), lettered, or arranged in alphabetical order. Downtown San Diego uses all three schemes: north-south streets are numbered from west to east, and east-west streets are split between a lettered series running southward from A through L and a series of streets named after trees or plants, running northward alphabetically from Ash to Walnut. As in many cities, some of these streets have been given new names violating the system (the former D Street is now Broadway, the former 12th Avenue is now Park Boulevard, etc.); this has meant that 2nd, not 1st, is the most common street name in the United States.

An exception to the typical, uniform grid is the plan of Savannah, Georgia (1733), known as the Oglethorpe Plan. It is a composite, cellular city block consisting of four large corner blocks, four small blocks in between and a public square in the centre; the entire composition of approximately ten acres (four hectares) is known as a ward. Its cellular structure includes all the primary land uses of a neighborhood and has for that reason been called fractal. Its street configuration presages modern traffic calming techniques applied to uniform grids where certain selected streets become discontinuous or narrow, thus discouraging through traffic. The configuration also represents an example of functional shared space, where pedestrian and vehicular traffic can safely and comfortably coexist.

In the westward development of the United States, the use of the grid plan was nearly universal in the construction of new settlements, such as in Salt Lake City (1870), Dodge City (1872) and Oklahoma City (1890). In these western cities the streets were numbered even more carefully than in the east to suggest future prosperity and metropolitan status.

One of the main advantages of the grid plan was that it allowed the rapid subdivision and auction of a large parcel of land. For example, when the legislature of the Republic of Texas decided in 1839 to move the capital to a new site along the Colorado River, the functioning of the government required the rapid population of the town, which was named Austin. Charged with the task, Edwin Waller designed a fourteen-block grid that fronted the river on 640 acres (exactly 1 square mile; about 2.6 km²). After surveying the land, Waller organized the almost immediate sale of 306 lots, and by the end of the year the entire Texas government had arrived by oxcart at the new site. Apart from the speed of surveying advantage, the rationale at the time of the grid’s adoption in this and other cities remains obscure.

Ildefonso Cerdá, a Spanish civil engineer, defined a concept of urban planning, based on the grid, that he applied to the Eixample of Barcelona. The Eixample grid introduced innovative design elements which were exceptional at the time and even unique among subsequent grid plans:

These innovations he based on functional grounds: the block size, to enable the creation of a quiet interior open space (60 m by 60 m) and allow ample sunlight and ventilation to its perimeter buildings; the rectilinear geometry, the wide streets and boulevards to sustain high mobility and the truncated corners to facilitate turning of carts and coaches and particularly vehicles on fixed rails.

In maps of larger American cities the downtown areas are almost always grids. These areas represent the original land dimensions of the founded city, generally around one square mile. Some cities expanded the grid further out from the centre, but maps also show that, in general, as the distance from the centre increases, a variety of patterns emerge in no particular discernible order. In juxtaposition to the grid they appear random. These new patterns have been systematically classified and their design characteristics measured.

In the United States, the grid system was widely used in most major cities and their suburbs until the 1960s. However, during the 1920s, the rapid adoption of the automobile caused a panic among urban planners, who, based on observation, claimed that speeding cars would eventually kill tens of thousands of small children per year. Apparently, at this early stage of the car’s entry into the grid, the streets of major cities worldwide were the scene of virtual “slaughter” as the fatality rate in proportion to population was more than double the current rate. In 2009, after several decades of road safety improvements and a continuous decline in fatalities, an estimated 33,963 people died in motor vehicle traffic crashes and, according to the National Highway Traffic Safety Administration, “Motor vehicle crashes are the leading cause of death for children from 3 to 14 years old.” Planners, therefore, called for an inwardly focused “superblock” arrangement that minimized through automobile traffic and discouraged cars from traveling on anything but arterial roads; traffic generators, such as apartment complexes and shops, would be restricted to the edges of the superblock, along the arterial. This paradigm prevailed between about 1930 and 1960, especially in Los Angeles, where notable examples include Leimert Park (an early example) and Panorama City (a late-period one).

A prominent 20th century urbanist, Lewis Mumford, severely criticized some of the grid’s characteristics: “With a T-square and a triangle, finally, the municipal engineer could, without the slightest training as either an architect or a sociologist, ‘plan’ a metropolis, with its standard lots, its standard blocks, its standard street widths, in short, with its standardized comparable, and replaceable parts. The new gridiron plans were spectacular in their inefficiency and waste. By usually failing to discriminate sufficiently between main arteries and residential streets, the first were not made wide enough while the second were usually too wide for purely neighborhood functions… as for its contribution to the permanent social functions of the city, the anonymous gridiron plan proved empty.”

In the 1960s, traffic engineers and urban planners abandoned the grid virtually wholesale in favor of a “street hierarchy”. This is a thoroughly “asymmetric” street arrangement in which a residential subdivision—often surrounded by a noise wall or a security gate—is completely separated from the road network except for one or two connections to arterial roads. In a way, this is a return to medieval styles: as noted in Spiro Kostof’s seminal history of urban design, The City Shaped, there is a strong resemblance between the street arrangements of modern American suburbs and those of medieval Arab and Moorish cities. In each case, the community unit at hand—the clan or extended family in the Muslim world, the economically homogeneous subdivision in modern suburbia—isolates itself from the larger urban scene by using dead ends and culs-de-sac.

One famous grid system is in the British new town of Milton Keynes. In this planned city, which began construction in 1967, a system of ten “horizontal” (roughly east-west) and eleven “vertical” (roughly north-south) roads was used, with roundabouts at each intersection. The horizontal roads were all given names ending in ‘way’ and H numbers (for ‘horizontal’, e.g. H3 Monks Way). The vertical roads were given names ending in ‘street’ and V numbers (for ‘vertical’, e.g. V6 Grafton Street). Each grid road was spaced roughly one kilometre along from the next, forming squares of approximately one square kilometre. Each square and each roundabout was given its own name. The system provided very easy transport within the city, although it confused visitors who were unfamiliar with the system. The grid squares thus formed are far larger than the city blocks described earlier, and the road layouts within the grid squares are generally ‘organic’ in form – matching the street hierarchy model described above.

Street width, or right of way (ROW), influences the amount of land that is devoted to streets, which becomes unavailable for development and therefore represents an opportunity cost. The wider the street the higher the opportunity cost. Street width is determined by circulation and aesthetic considerations and is not dependent on the pattern configuration. Any configuration can have wide or narrow streets.

Street length influences proportionately the amount of street components that have to be constructed such as pavement, curbs and sidewalks, storm sewers and drains, light poles, and trees. The street length of a given area of development depends on the frequency at which streets occur which in turn depends on the length and width of a block. The higher the frequency of streets the longer is their total length. The smaller the block dimensions the higher the frequency of the streets. As the frequency of street increases so does the number of intersections. Intersections normally cost more than straight street length because they are labour-intensive and require street and traffic signage.

Pavement width influences the cost by affecting the amount of materials and labour required to provide a finished road surface. Pavement width is generally based on traffic engineering considerations and is not dependent on pattern configuration. As with the street width, any pattern can have wide or narrow pavements. Of all three factors that affect cost, street width, street length and pavement width, only street length is pattern dependent. An objective cost comparison would, therefore, rely on this variable with the full understanding that the other variables, though optional, can play a role.

Traditional orthogonal grid patterns generally have greater street frequencies than discontinuous patterns. For example, Portland’s block is 200 feet × 200 feet while Miletus’ is half that size and Timgad’s half again (see diagram). Houston, Sacramento and Barcelona are progressively bigger reaching up to four times the area of Portland’s block. New York’s 1811 plan (see above) has blocks of 200 feet (61 m). in width and variable lengths ranging from about 500 to 900 feet. The corresponding frequency of streets for each of these block sizes affects the street length.

A simple example of a grid street pattern (see diagram) illustrates the progressive reduction in total street length (the sum of all individual street lengths) and the corresponding increase in block length. For a corresponding reduction of one, two, three and four streets within this 40-acre (16 ha) parcel, the street length is reduced from an original total of 12,600 to 7,680 linear feet, a 39% reduction. Simultaneously, block lengths increase from 200 × 200 feet to 1240 × 200 feet. When all five blocks have reached the ultimate size of 1,240 feet (380 m) four street lengths out of total eight have been eliminated. Block lengths of 1000 feet or larger rarely appear in grid plans and are not recommended as they hinder pedestrian movement (Pedestrianism, below). From the pedestrian perspective, the smaller the block is, the easier the navigation and the more direct the route. Consequently, the finer grids are preferred.

Patterns that incorporate discontinuous street types such as crescents and culs-de-sac have not, in general, regarded pedestrian movement as a priority and, consequently, have produced blocks that are usually in the 1000-foot range and often exceed it. As a result, street frequency drops and so does the total street length and, therefore, the cost. In general, it is not the street pattern per se that affects costs but the frequency of streets that it either necessitates or purposely incorporates.

An inherent advantage of the orthogonal geometry of a proper grid is its tendency to yield regular lots in well-packed sequences. This maximizes the use of the land of the block; it does not, however, affect street frequency. Any frequency of orthogonal streets produces the same packing effect. Orthogonal geometry also minimizes disputes over lot boundaries and maximizes the number of lots that could front a given street. John Randal said Manhattan’s grid plan facilitated “buying, selling and improving real estate”.

Another important aspect of street grids and the use of rectilinear blocks is that traffic flows of either pedestrians, cars, or both, only cross at right angles. This is an important traffic safety feature, since no one entering the intersection needs to look over their shoulder to see oncoming traffic. Any time traffic flows meet at an acute angle, someone cannot see traffic approaching them. The grid is thus a geometric response to our human physiology. It is very likely the original purpose of grid layouts comes from the Athenian Agora. Before the grid organization, markets were laid out randomly in a field with traffic approaches at odd angles. This caused carts and wagons to turn over due to frequent collisions. Laying out the market stalls into regularized rows at right angles solved this problem and was later built into the Athenian Agora and copied ever since.

Typical uniform grids are unresponsive to topography. Priene’s plan, for example, is set on a hill side and most of its north-south streets are stepped, a feature that would have made them inaccessible to carts, chariots and loaded animals. Many modern cities, such as San Francisco, Vancouver, and Saint John, New Brunswick, follow Priene’s example, e.g.. In a modern context, steep grades limit accessibility by car, and more so by bicycle, on foot, or wheelchair, particularly in cold climates.

The same inflexibility of the grid leads to disregarding environmentally sensitive areas such as small streams and creeks or mature woodlots in preference for the application of the immutable geometry. It is said of the NY grid plan that it flattened all obstacles in its way. By contrast, recent discontinuous street patterns follow the configuration of natural features without disrupting them. The grid represents a rationalist, reductionist solution to a multifaceted issue.

The grid’s inherent high street and intersection frequencies produce large areas of impermeable surfaces in the street pavement and the sidewalks. In comparison to recent networks with discontinuous street types, grids can be up to 30% higher in impermeable surfaces attributable to roads. The emerging environmental priority of retaining as much as 90% of rain water on site becomes problematic with high percentages of impermeable surfaces. And since roads constitute the largest share of the total impermeable surfaces of a development, the difficulty is compounded by the grid type of layout. For these reasons modern planners have attempted to modify the rigid, uniform, classic grid.

Some cities, notably Seattle, have devised means to improve a street’s retention capacity. However, frequent intersections as they occur in a regular grid would pose an obstacle to their effective application.

A street network pattern can affect the production of pollutants by the amount of car travel that it necessitates and the speed at which cars can travel. The grid plan with its frequent intersections may displace a portion of the local car trips with walking or biking due to the directness of route that it offers to pedestrians. But it also makes the same routes more direct for cars, which could be an enticement for driving. The potential car trip displacement would result in a reduction of pollutant emissions. The advantage of the intersection density for pedestrians, however, can have a contrary effect for cars due to its potential for reducing speeds. Low speeds below 20 mph have a significantly higher coefficient of pollutant production than above 30, though the coefficient after leveling off tends to increase gradually after 50 mph. This effect is accentuated with high traffic density in areas with commercial uses where speeds come to a crawl. Since the grid plan is non-hierarchical and intersections are frequent, all streets can be subject to this potential reduction of average speeds, leading to a high production of pollutants. Greenhouse and noxious gases can be detrimental to the environment and to resident health.

In his seminal study (1982) on livable streets that was conducted in neighbourhoods with a grid, Donald Appleyard showed that social networking and street playing degraded as traffic increased on a street. His research provided the groundwork for traffic calming and for several initiatives such as living streets and Home Zones, all of which are aimed at improving a street’s social milieu. The amount of traffic on a street depends on variables such as the population density of the neighbourhood, car ownership and its proximity to commercial, institutional or recreational edifices. Most importantly, however, it depends on whether a street is or could become a through road to a destination. As a through road, it could sustain unpredictable levels of traffic that may fluctuate during the day and increase over time.

A key characteristic of the grid pattern is that any and all streets are equally accessible to traffic (non-hierarchical) and could be chosen at will as alternative routes to a destination. Cut-through driving, or shortcutting, has been resisted by residents. Cities responded by making modifications to prevent it. Current recommended design practice suggests the use of 3-way intersections to alleviate it.

The geometry of the normal, open grid is evidently unsuitable for protecting or enhancing the social environment of a street from the negative influence of traffic. Similarly, a 1972 ground-breaking study by Oscar Newman on a Defensible Space Theory described ways to improve the social environment and security of neighbourhoods and streets. In a practical application of his theory at Five Oaks, the neighbourhood’s grid pattern was modified to prevent through traffic and create identifiable smaller enclaves while maintaining complete pedestrian freedom of movement. The positive outcome of these changes reinforces Appleyard’s findings and the need to reduce or prevent through traffic on neighbourhood streets; a need that cannot be met with a typical, uniform, open grid.

The question of neighbourhood security has been a constant focus of research since Oscar Newman’s work. New research has expanded the discussion on this disputed issue. A recent study did extensive spatial analysis and correlated several building, site plan and social factors with crime frequencies and identified subtle nuances to the contrasting positions. The study looked at, among others, dwelling types, unit density (site density) movement on the street, culs–de-sac or grids and the permeability of a residential area. Among its conclusions are, respectively, that flats are always safer than houses and the wealth of inhabitants matters, density is generally beneficial but more so at ground level, local movement is beneficial, but not larger scale movement, relative affluence and the number of neighbours have a greater effect than either being on a cul-de-sac or being on a through street. It also re-established that simple, linear culs-de-sac with good numbers of dwellings that are joined to through streets tend to be safe. As for permeability, it suggests that residential areas should be permeable enough to allow movement in all directions but no more. The overprovision of poorly used permeability is a crime hazard. The open, uniform grid could be seen as an example of undifferentiated permeability.

A recent study in California examined the amount of child play that occurred on the streets of neighbourhoods with different characteristics; grid pattern and culs-de-sac. The findings indicate that the open grid streets showed substantially lower play activity than the cul-de-sac street type. Culs-de-sac reduce perceived danger from traffic thereby encouraging more outdoor play. It pointed the way toward the development of hybrid street network patterns that improve pedestrian movement but restrict cut-through driving. Similar studies in Europe and most recently in Australia found that children’s outdoor play is significantly reduced on through roads where traffic is, or perceived by parents to be, a risk.

Traditional street functions such as kids’ play, strolling and socializing are incompatible with traffic flow, which the open, uniform grid geometry encourages. For these reasons, cities such as Berkeley, California, and Vancouver, British Columbia, among many others, transformed existing residential streets part of a grid plan into permeable, linked culs-de-sac. This transformation retains the permeability and connectivity of the grid for the active modes of transport but filters and restricts car traffic on the cul-de-sac street to residents only.

Street networks of old cities that grew organically, though admired for being picturesque, can be confusing for visitors but rarely for the original inhabitants (see plan). Similarly confusing to visitors are the plans of modern subdivisions with discontinuous and curvilinear streets. Change of street orientation, particularly when gradual or arbitrary, cannot be “mapped” in the mind. Impasses, crescents or cul-de-sacs frustrate the traveler especially when they are long, forcing an arduous retracing of steps.

Frequency of intersections, however, becomes also a disadvantage for pedestrians and bicycles. It disrupts the relaxed canter of walking and forces pedestrians repeatedly onto the road, a hostile, anxiety-generating territory. People with physical limitations or frailties, children and seniors for example, can find a regular walk challenging. For bicycles this disadvantage is accentuated as their normal speed is at least double that of pedestrians. Frequent stops negate the speed advantage and the physical benefit of bicycling and add to frustration.[citation needed] Intersections are not only unpleasant but also dangerous. Most traffic collisions and injuries occur at intersections and the majority of the injuries to pedestrians crossing with the right of way.

A dilemma arises from trying to meet important planning objectives when using the grid: pedestrianism, cost efficiency and environmental responsiveness. To serve pedestrians well, a rectangular configuration and high frequency of streets and intersections is the preferred route, which the orthogonal grid geometry provides. To reduce development costs and environmental impact, lower frequency of streets is the logical path. Since these two design objectives are contradictory a balance needs to be struck. Such balance has been achieved in leading modern projects such as Vauban, Freiburg and Village Homes, Davis. Both score high in pedestrian and bike mode share and, at the same time, in reducing negative development externalities. Their layout configurations represent a fusion of the classic grid plan with recent street network patterns.

Examining the issue of walkability, a recent comparison of seven neighbourhood layouts found a 43 and 32 percent increase in walking with respect to a grid plan and conventional suburban layout in a fused grid layout, which has greater permeability for pedestrians than for cars due to its inclusion of dedicated pedestrian paths. It also showed a 7 to 10 percent range of reduction in driving with respect to the remainder six neighbourhood layouts in the set, an environmental benefit.

Perceived and actual safety play a role in the use of the street. Perceived safety, though perhaps an inaccurate reflection of the number of injuries or fatalities, influences parents’ decision to allow their children to play, walk or bike on the street. Actual levels of safety as measured by the total number of collisions and the number and severity of injuries are a matter of public concern. Both should inform the layout, if the street network is to achieve its optimum use.

Recent studies have found higher traffic fatality rates in outlying suburban areas than in central cities and inner suburbs with smaller blocks and more-connected street patterns. While some of this disparity is the result of distance from emergency medical facilities (hospitals are usually built in a fairly late stage of the development of a suburban area), it is clear[citation needed] that the lower speeds encouraged by the frequency of intersections decrease the severity of accidents occurring on streets within a grid plan.

An earlier study found significant differences in recorded accidents between residential neighbourhoods that were laid out on a grid and those that included culs-de-sac and crescents. The frequency of accidents was significantly higher in the grid neighbourhoods.

Two newer studies examined the frequency of collisions in two regional districts using the latest analytical tools. They investigated the potential correlation between street network patterns and frequency of collisions. In one study, cul-de-sac networks appeared to be much safer than grid networks, by nearly three to one. A second study found the grid plan to be the least safe by a significant margin with respect to all other street patterns.

A 2009 study suggests that land use patterns play a significant role in traffic safety and should be considered in conjunction with the network pattern. While all intersection types in general reduce the incidence of fatal crashes, four-way intersections, which occur regularly in a grid, increase total and injurious crashes significantly. The study recommends hybrid street networks with dense concentrations of T-intersections and concludes that a return to the 19th century gridiron is undesirable.

Stringent adherence to the grid plan can cause steep inclines since the topology of the land is not taken into account. This may be unsafe for drivers, pedestrians and bicycles since it is more difficult to control speed and braking, particularly in winter conditions.

One of the greatest difficulties with grid plans is their lack of specialisation, most of the important amenities being concentrated along the city’s main arteries. Often grid plans are found in linear settlements, with a main street connecting between the perpendicular roads. However, this can be mitigated by allowing mixed use development so that destinations become closer to home. Many cities, especially in Latin America, still successfully retain their grid plans. Recently, planners in the United States and Canada have revisited the idea of reintroducing grid patterns to many cities and towns.

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