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Traffic Jams
Traffic congestion is a condition in transport that is characterized by slower speeds, longer trip times, and increased vehicular queueing. Traffic congestion on urban road networks has increased substantially since the 1950s. When traffic demand is great enough that the interaction between vehicles slows the speed of the traffic stream, this results in some congestion. While congestion is a possibility for any mode of transportation, this article will focus on automobile congestion on public roads. As demand approaches the capacity of a road (or of the intersections along the road), extreme traffic congestion sets in. When vehicles are fully stopped for periods of time, this is known as a traffic jam or (informally) a traffic snarl-up. Traffic congestion can lead to drivers becoming frustrated and engaging in road rage. Mathematically, traffic is modeled as a flow through a fixed point on the route, analogously to fluid dynamics. Causes Traffic congestion occurs when ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philip Ball
Philip Ball (born 1962) is a British science writer. For over twenty years he has been an editor of the journal ''Nature'' for which he continues to write regularly. He now writes a regular column in '' Chemistry World''. He has contributed to publications ranging from ''New Scientist'' to the ''New York Times'', ''The Guardian'', the ''Financial Times'' and ''New Statesman''. He is the regular contributor to '' Prospect'' magazine, and also a columnist for ''Chemistry World'', ''Nature Materials'' and BBC Future. He has broadcast on many occasions on radio and TV, and in June 2004 he presented a three-part serial on nanotechnology, ''Small Worlds'', on BBC Radio 4. Work Ball's 2004 book '' Critical Mass: How One Thing Leads to Another'' was the winner of the 2005 Aventis Prize for Science Books. It examines a wide range of topics including the business cycle, random walks, phase transitions, bifurcation theory, traffic flow, Zipf's law, Small world phenomenon, catastrophe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Traffic Jam In Haikou, Hainan, China 01
Traffic comprises pedestrians, vehicles, ridden or herded animals, trains, and other conveyances that use public ways (roads) for travel and transportation. Traffic laws govern and regulate traffic, while rules of the road include traffic laws and informal rules that may have developed over time to facilitate the orderly and timely flow of traffic. Organized traffic generally has well-established priorities, lanes, right-of-way, and traffic control at intersections. Traffic is formally organized in many jurisdictions, with marked lanes, junctions, intersections, interchanges, traffic signals, or signs. Traffic is often classified by type: heavy motor vehicle (e.g., car, truck), other vehicle (e.g., moped, bicycle), and pedestrian. Different classes may share speed limits and easement, or may be segregated. Some jurisdictions may have very detailed and complex rules of the road while others rely more on drivers' common sense and willingness to cooperate. Organization ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Road Works
Roadworks (called road work or road construction in the United States) occur when part of the road, or in rare cases, the entire road, has to be occupied for work relating to the road, most often in the case of road surface repairs. In the United States road work could also mean any work conducted in close proximity of travel way (thoroughfare) such as utility work or work on power lines (i.e. telephone poles). The general term of road work is known as work zone. Roadworks can, however, also happen when a major accident occurs and road debris from the crash needs to be cleared. Roadworks are often signposted, although it is possible that the signage comes too late or too sudden or is missing. Typical road work traffic controls are temporary signs, traffic cones, barrier boards and t-top bollards as well as other forms of warning devices. There are standards of temporary traffic control (maintenance of traffic) established in each country for various type of road work. Roadwo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Road Pricing
Road pricing (also road user charges) are direct charges levied for the use of roads, including road tolls, distance or time-based fees, congestion charges and charges designed to discourage the use of certain classes of vehicle, fuel sources or more polluting vehicles. These charges may be used primarily for revenue generation, usually for road infrastructure financing, or as a transportation demand management tool to reduce peak hour travel and the associated traffic congestion or other social and environmental negative externalities associated with road travel such as air pollution, greenhouse gas emissions, visual intrusion, noise pollution and road traffic collisions. ''Executive Summary, pp. v''. In most countries toll roads, toll bridges and toll tunnels are often used primarily for revenue generation to repay long-term debt issued to finance the toll facility, or to finance capacity expansion, operations, and maintenance of the facility itself, or simply as genera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Private Highway
A private highway is a highway owned and operated for profit by private industry. Private highways are common in Asia and Europe; in addition, a few have been built in the United States on an experimental basis. Typically, private highways are built by companies that charge tolls for a period while the debt is retired, after which the highway is turned over to government control. This allows governments to fulfill immediate transportation needs despite their own budget constraints, while still retaining public ownership of the roads in the long term. An obstacle to private highways is that government regulation can stifle price flexibility and introduce negotiation and paperwork requirements that increase operational expenses, while having to compete against free public roads. In addition, private highways lack some advantages that governments have, such as sovereign immunity against liability for accidents, the use of eminent domain power to acquire private property for roads and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opportunity Cost
In microeconomic theory, the opportunity cost of a particular activity is the value or benefit given up by engaging in that activity, relative to engaging in an alternative activity. More effective it means if you chose one activity (for example, an investment) you are giving up the opportunity to do a different option. The optimal activity is the one that, net of its opportunity cost, provides the greater return compared to any other activities, net of their opportunity costs. For example, if you buy a car and use it exclusively to transport yourself, you cannot rent it out, whereas if you rent it out you cannot use it to transport yourself. If your cost of transporting yourself without the car is more than what you get for renting out the car, the optimal choice is to use the car yourself. In basic equation form, opportunity cost can be defined as: "Opportunity Cost = (returns on best Forgone Option) - (returns on Chosen Option)." The opportunity cost of mowing one’s own la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tragedy Of The Commons
Tragedy (from the grc-gre, τραγῳδία, ''tragōidia'', ''tragōidia'') is a genre of drama based on human suffering and, mainly, the terrible or sorrowful events that befall a main character. Traditionally, the intention of tragedy is to invoke an accompanying catharsis, or a "pain hatawakens pleasure", for the audience. While many cultures have developed forms that provoke this paradoxical response, the term ''tragedy'' often refers to a specific tradition of drama that has played a unique and important role historically in the self-definition of Western civilization. That tradition has been multiple and discontinuous, yet the term has often been used to invoke a powerful effect of cultural identity and historical continuity—"the Greeks and the Elizabethans, in one cultural form; Hellenes and Christians, in a common activity," as Raymond Williams puts it. From its origins in the theatre of ancient Greece 2500 years ago, from which there survives only a fraction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Entropy
Entropy is a scientific concept, as well as a measurable physical property, that is most commonly associated with a state of disorder, randomness, or uncertainty. The term and the concept are used in diverse fields, from classical thermodynamics, where it was first recognized, to the microscopic description of nature in statistical physics, and to the principles of information theory. It has found far-ranging applications in chemistry and physics, in biological systems and their relation to life, in cosmology, economics, sociology, weather science, climate change, and information systems including the transmission of information in telecommunication. The thermodynamic concept was referred to by Scottish scientist and engineer William Rankine in 1850 with the names ''thermodynamic function'' and ''heat-potential''. In 1865, German physicist Rudolf Clausius, one of the leading founders of the field of thermodynamics, defined it as the quotient of an infinitesimal amount of hea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Traffic Flow
In mathematics and transportation engineering, traffic flow is the study of interactions between travellers (including pedestrians, cyclists, drivers, and their vehicles) and infrastructure (including highways, signage, and traffic control devices), with the aim of understanding and developing an optimal transport network with efficient movement of traffic and minimal traffic congestion problems. History Attempts to produce a mathematical theory of traffic flow date back to the 1920s, when Frank Knight first produced an analysis of traffic equilibrium, which was refined into John Glen Wardrop, Wardrop's first and second principles of equilibrium in 1952. Nonetheless, even with the advent of significant computer processing power, to date there has been no satisfactory general theory that can be consistently applied to real flow conditions. Current traffic models use a mixture of empirical and Deductive reasoning, theoretical techniques. These models are then developed into Trans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
