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Bollard Aboard The RV Thomas G
A bollard is a sturdy, short, vertical post. The term originally referred to a post on a ship or quay used principally for mooring boats. It now also refers to posts installed to control road traffic and posts designed to prevent automotive vehicles from colliding or crashing into pedestrians and structures, whether intentional from ram-raids and vehicle-ramming attacks, or unintentional losses of control. Etymology The term is probably related to bole, meaning a tree trunk. The earliest citation given by the ''Oxford English Dictionary'' (referring to a maritime bollard) dates from 1844, although a reference in the ''Caledonian Mercury'' in 1817 describes bollards as huge posts. History Wooden posts were used for basic traffic management from at least the beginning of the 18th century. An early well-documented case is that of the "two oak-posts" set up next to the medieval Eleanor cross at Waltham Cross, Hertfordshire, in 1721, at the expense of the Society of Antiqu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Highway Exit
In the field of road transport, an interchange (American English) or a grade-separated junction (British English) is a road junction that uses grade separations to allow for the movement of traffic between two or more roadways or highways, using a system of interconnecting roadways to permit traffic on at least one of the routes to pass through the junction without interruption from crossing traffic streams. It differs from a standard intersection, where roads cross at grade. Interchanges are almost always used when at least one road is a controlled-access highway (freeway or motorway) or a limited-access divided highway (expressway), though they are sometimes used at junctions between surface streets. Terminology ''Note:'' The descriptions of interchanges apply to countries where vehicles drive on the right side of the road. For left-side driving, the layout of junctions is mirrored. Both North American (NA) and British (UK) terminology is included. ; Freeway junction, h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bell Bollard
A bell is a directly struck idiophone percussion instrument. Most bells have the shape of a hollow cup that when struck vibrates in a single strong strike tone, with its sides forming an efficient resonator. The strike may be made by an internal "clapper" or "uvula", an external hammer, or—in small bells—by a small loose sphere enclosed within the body of the bell (jingle bell). Bells are usually cast from bell metal (a type of bronze) for its resonant properties, but can also be made from other hard materials. This depends on the function. Some small bells such as ornamental bells or cowbells can be made from cast or pressed metal, glass or ceramic, but large bells such as a church, clock and tower bells are normally cast from bell metal. Bells intended to be heard over a wide area can range from a single bell hung in a turret or bell-gable, to a musical ensemble such as an English ring of bells, a carillon or a Russian zvon which are tuned to a common scale and installe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retroreflection
A retroreflector (sometimes called a retroflector or cataphote) is a device or surface that reflects radiation (usually light) back to its source with minimum scattering. This works at a wide range of angle of incidence, unlike a planar mirror, which does this only if the mirror is exactly perpendicular to the wave front, having a zero angle of incidence. Being directed, the retroflector's reflection is brighter than that of a diffuse reflector. Corner reflectors and cat's eye reflectors are the most used kinds. Types There are several ways to obtain retroreflection: Corner reflector A set of three mutually perpendicular reflective surfaces, placed to form the internal corner of a cube, work as a retroreflector. The three corresponding normal vectors of the corner's sides form a basis in which to represent the direction of an arbitrary incoming ray, . When the ray reflects from the first side, say x, the ray's ''x''-component, ''a'', is reversed to −''a'', while the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transportation Research Board
The Transportation Research Board (TRB) is a division of the National Academy of Sciences, Engineering, and Medicine, formerly the National Research Council of the United States, which serves as an independent adviser to the President of the United States, the Congress and federal agencies on scientific and technical questions of national importance. It is jointly administered by the National Academy of Sciences, the National Academy of Engineering, and the National Academy of Medicine. As one of seven major divisions of the National Academies of Sciences, Engineering, and Medicine, TRB promotes innovation and progress in transportation through research in an objective and interdisciplinary setting. It provides trusted, timely, impartial, and evidence-based information exchange, research, and advice regarding all modes of transportation. TRB hosts some 200 standing technical committees that address specific aspects of transport and the TRB Annual Meeting attracts thousands of trans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Street Light
A street light, light pole, lamp pole, lamppost, street lamp, light standard, or lamp standard is a raised source of light on the edge of a road or path. Similar lights may be found on a railway platform. When urban electric power distribution became ubiquitous in developed countries in the 20th century, lights for urban streets followed, or sometimes led. Many lamps have light-sensitive photocells that activate the lamp automatically when needed, at times when there is little-to-no ambient light, such as at dusk, dawn, or at the onset of dark weather conditions. This function in older lighting systems could be performed with the aid of a solar dial. Many street light systems are being connected underground instead of wiring from one utility post to another. Street lights are an important source of public security lighting intended to reduce crime. History Preindustrial era Early lamps were used by Greek and Roman civilizations, where light primarily served the purpose of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Traffic Sign
Traffic signs or road signs are signs erected at the side of or above roads to give instructions or provide information to road users. The earliest signs were simple wooden or stone milestones. Later, signs with directional arms were introduced, for example the fingerposts in the United Kingdom and their wooden counterparts in Saxony. With traffic volumes increasing since the 1930s, many countries have adopted pictorial signs or otherwise simplified and standardized their signs to overcome language barriers, and enhance traffic safety. Such pictorial signs use symbols (often silhouettes) in place of words and are usually based on international protocols. Such signs were first developed in Europe, and have been adopted by most countries to varying degrees. International conventions Various international conventions have helped to achieve a degree of uniformity in Traffic Signing in various countries. Categories Traffic signs can be grouped into several types. For example, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bollards2742Canthusus
A bollard is a sturdy, short, vertical post. The term originally referred to a post on a ship or quay used principally for mooring boats. It now also refers to posts installed to control road traffic and posts designed to prevent automotive vehicles from colliding or crashing into pedestrians and structures, whether intentional from ram-raids and vehicle-ramming attacks, or unintentional losses of control. Etymology The term is probably related to bole, meaning a tree trunk. The earliest citation given by the ''Oxford English Dictionary'' (referring to a maritime bollard) dates from 1844, although a reference in the ''Caledonian Mercury'' in 1817 describes bollards as huge posts. History Wooden posts were used for basic traffic management from at least the beginning of the 18th century. An early well-documented case is that of the "two oak-posts" set up next to the medieval Eleanor cross at Waltham Cross, Hertfordshire, in 1721, at the expense of the Society of Antiquari ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intersection (road)
An intersection or an at-grade junction is a junction where two or more roads converge, diverge, meet or cross at the same height, as opposed to an interchange, which uses bridges or tunnels to separate different roads. Major intersections are often delineated by gores and may be classified by road segments, traffic controls and lane design. Types Road segments One way to classify intersections is by the number of road segments (arms) that are involved. * A three-way intersection is a junction between three road segments (arms): a T junction when two arms form one road, or a Y junction, the latter also known as a fork if approached from the stem of the Y. * A four-way intersection, or crossroads, usually involves a crossing over of two streets or roads. In areas where there are blocks and in some other cases, the crossing streets or roads are perpendicular to each other. However, two roads may cross at a different angle. In a few cases, the junction of two road segments ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sidewalks
A sidewalk (North American English), pavement (British English), footpath in Australia, India, New Zealand and Ireland, or footway, is a path along the side of a street, highway, terminals. Usually constructed of concrete, pavers, brick, stone, or asphalt, it is designed for pedestrians. A sidewalk is normally higher than the roadway, and separated from it by a kerb (spelled "curb" in North America). There may also be a planted strip between the sidewalk and the roadway and between the roadway and the adjacent land. In some places, the same term may also be used for a paved path, trail or footpath that is not next to a road, for example, a path through a park. Terminology The term "sidewalk" is preferred in most of North America. The term "pavement" is more common in the United Kingdom and other members of the Commonwealth of Nations, as well as parts of the Mid-Atlantic United States such as Philadelphia and parts of New Jersey. Many Commonwealth countries use the term "f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
