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Mean Velocity
The fundamental diagram of traffic flow is a diagram that gives a relation between road traffic flux (vehicles/hour) and the traffic density (vehicles/km). A macroscopic traffic model involving traffic flux, traffic density and velocity forms the basis of the fundamental diagram. It can be used to predict the capability of a road system, or its behaviour when applying inflow regulation or speed limits. Basic statements * There is a connection between traffic density and vehicle velocity: The more vehicles are on a road, the slower their velocity will be. * To prevent congestion and to keep traffic flow stable, the number of vehicles entering the control zone has to be smaller or equal to the number of vehicles leaving the zone in the same time. * At a critical traffic density and a corresponding critical velocity the state of flow will change from stable to unstable. * If one of the vehicles brakes in unstable flow regime the flow will collapse. The primary tool for graphically ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diagram
A diagram is a symbolic Depiction, representation of information using Visualization (graphics), visualization techniques. Diagrams have been used since prehistoric times on Cave painting, walls of caves, but became more prevalent during the Age of Enlightenment, Enlightenment. Sometimes, the technique uses a Three-dimensional space, three-dimensional visualization which is then graphical projection, projected onto a two-dimensional surface. The word ''graphics, graph'' is sometimes used as a synonym for diagram. Overview The term "diagram" in its commonly used sense can have a general or specific meaning: * ''visual information device'' : Like the term "illustration", "diagram" is used as a collective term standing for the whole class of technical genres, including graphics, graphs, technical drawings and tables. * ''specific kind of visual display'' : This is the genre that shows qualitative data with shapes that are connected by lines, arrows, or other visual links. In scie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Speed Limit
Speed limits on road traffic, as used in most countries, set the legal maximum speed at which vehicles may travel on a given stretch of road. Speed limits are generally indicated on a traffic sign reflecting the maximum permitted speed, expressed as kilometres per hour (km/h) or miles per hour (mph) or both. Speed limits are commonly set by the legislative bodies of national or provincial governments and enforced by national or regional police and judicial authorities. Speed limits may also be variable, or in some places nonexistent, such as on most of the Autobahnen in Germany. The first numeric speed limit for mechanically propelled road vehicles was the limit introduced in the United Kingdom in 1861. the highest posted speed limit in the world is , applied on two motorways in the United Arab Emirates, UAE. Speed limits and safety distance are poorly enforced in the UAE, specifically on the Abu Dhabi to Dubai motorway – which results in dangerous traffic, according to a F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fundamental Diagram
The fundamental diagram of traffic flow is a diagram that gives a relation between road traffic flux (vehicles/hour) and the traffic density (vehicles/km). A macroscopic traffic model involving traffic flux, traffic density and velocity forms the basis of the fundamental diagram. It can be used to predict the capability of a road system, or its behaviour when applying inflow regulation or speed limits. Basic statements * There is a connection between traffic density and vehicle velocity: The more vehicles are on a road, the slower their velocity will be. * To prevent congestion and to keep traffic flow stable, the number of vehicles entering the control zone has to be smaller or equal to the number of vehicles leaving the zone in the same time. * At a critical traffic density and a corresponding critical velocity the state of flow will change from stable to unstable. * If one of the vehicles brakes in unstable flow regime the flow will collapse. The primary tool for graphically ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fundamental Diagram Of PeMS-D4 Node 1
Fundamental may refer to: * Foundation of reality * Fundamental frequency, as in music or phonetics, often referred to as simply a "fundamental" * Fundamentalism, the belief in, and usually the strict adherence to, the simple or "fundamental" ideas based on faith in a system of thought * '' Fundamentals: Ten Keys to Reality'', a 2021 popular science book by Frank Wilczek * ''The Fundamentals'', a set of books important to Christian fundamentalism * Any of a number of fundamental theorems identified in mathematics, such as: ** Fundamental theorem of algebra, a theorem regarding the factorization of polynomials ** Fundamental theorem of arithmetic, a theorem regarding prime factorization * Fundamental analysis, the process of reviewing and analyzing a company's financial statements to make better economic decisions Music * Fun-Da-Mental, a rap group * ''Fundamental'' (Bonnie Raitt album), 1998 * ''Fundamental'' (Pet Shop Boys album), 2006 * ''Fundamental'' (Puya album) or the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sample Traffic Flow Macroscopic Fundamental Diagram
Sample or samples may refer to: * Sample (graphics), an intersection of a color channel and a pixel * Sample (material), a specimen or small quantity of something * Sample (signal), a digital discrete sample of a continuous analog signal * Sample (statistics), a subset of a population – complete data set People * Sample (surname) * Samples (surname) Places * Sample, Kentucky, unincorporated community, United States * Sampleville, Ohio, unincorporated community, United States * Hugh W. and Sarah Sample House, listed on the National Register of Historic Places in Iowa, United States Music * Sample (music), to reuse a portion of a sound recording in another recording, or the portion reused * "Sample" (Sakanaction song) * "Sample", a song by No-Man from ''Flowermix'' * The Samples, a band from Boulder, Colorado Other uses * USS ''Sample'' (FF-1048), a frigate in the U.S. Navy * The Sample, a defunct department store in Buffalo, New York, U.S. * SAMPLE history, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Time Space Diag Figure 2
Time is the continuous progression of existence that occurs in an apparently irreversible succession from the past, through the present, and into the future. It is a component quantity of various measurements used to sequence events, to compare the duration of events (or the intervals between them), and to quantify rates of change of quantities in material reality or in the conscious experience. Time is often referred to as a fourth dimension, along with three spatial dimensions. Time is one of the seven fundamental physical quantities in both the International System of Units (SI) and International System of Quantities. The SI base unit of time is the second, which is defined by measuring the electronic transition frequency of caesium atoms. General relativity is the primary framework for understanding how spacetime works. Through advances in both theoretical and experimental investigations of spacetime, it has been shown that time can be distorted and dilated, particularl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Congestion Pricing
Congestion pricing or congestion charges is a system of surcharging users of public goods that are subject to congestion through excess demand, such as through higher peak charges for use of bus services, electricity, metros, railways, telephones, and road pricing to reduce traffic congestion; airlines and shipping companies may be charged higher fees for slots at airports and through canals at busy times. This pricing strategy regulates demand, making it possible to manage congestion without increasing supply. According to the economic theory behind congestion pricing, the objective of this policy is to use the price mechanism to cover the social cost of an activity where users otherwise do not pay for the negative externalities they create (such as driving in a congested area during peak demand). By setting a price on an over-consumed product, congestion pricing encourages the redistribution of the demand in space or in time, leading to more efficient outcomes. Si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saturation (traffic)
In traffic engineering, saturation describes the maximum traffic flow which can be handled by a junction. The saturation flow is the rate at which a continuous flow of vehicles can pass through a constant green signal, typically expressed in vehicles per hour or PCUs per hour. A formula to calculate saturation flows based on lane geometry is given in Transport and Road Research Laboratory RR67. However, the formula can over-estimate saturation flows at congested locations. Degree of Saturation The degree of saturation (DoS) of an intersection (typically under traffic signal control) or a link measures the demand relative to the total capacity. A DoS value of 100% meaning that demand and capacity are equal and no further traffic is able to progress through the junction. The formula to calculate DoS is: *Degree of saturation = (demand x cycle time) / (saturation flow x effective green time) Values over 85%-90% typically indicate traffic congestion Traffic congestion is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smith Predictor
The Smith predictor (invented by O. J. M. Smith in 1957) is a type of predictive controller designed to control systems with a significant feedback time delay. The idea can be illustrated as follows. Suppose the plant consists of G(z) followed by a pure time delay z^. z refers to the Z-transform of the transfer function relating the inputs and outputs of the plant G. As a first step, suppose we only consider G(z) (the plant without a delay) and design a controller C(z) with a closed-loop transfer function H(z)=\frac that we consider satisfactory. Next, our objective is to design a controller \bar(z) for the plant G(z) z^ so that the closed loop transfer function \bar(z) equals H(z) z^. Solving \frac = z^ \frac, we obtain \bar = \frac. The controller is implemented as shown in the following figure, where G(z) has been changed to \hat(z) to indicate that it is a model used by the controller. Note that there are two feedback loops. The outer control loop feeds the output ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Control Engineering
Control engineering, also known as control systems engineering and, in some European countries, automation engineering, is an engineering discipline that deals with control systems, applying control theory to design equipment and systems with desired behaviors in control environments. The discipline of controls overlaps and is usually taught along with electrical engineering, chemical engineering and mechanical engineering at many institutions around the world. The practice uses sensors and detectors to measure the output performance of the process being controlled; these measurements are used to provide corrective feedback helping to achieve the desired performance. Systems designed to perform without requiring human input are called automatic control systems (such as cruise control for regulating the speed of a car). Multi-disciplinary in nature, control systems engineering activities focus on implementation of control systems mainly derived by mathematical modeling of a diver ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PI Controller
The number (; spelled out as pi) is a mathematical constant, approximately equal to 3.14159, that is the ratio of a circle's circumference to its diameter. It appears in many formulae across mathematics and physics, and some of these formulae are commonly used for defining , to avoid relying on the definition of the length of a curve. The number is an irrational number, meaning that it cannot be expressed exactly as a ratio of two integers, although fractions such as \tfrac are commonly used to approximate it. Consequently, its decimal representation never ends, nor enters a permanently repeating pattern. It is a transcendental number, meaning that it cannot be a solution of an algebraic equation involving only finite sums, products, powers, and integers. The transcendence of implies that it is impossible to solve the ancient challenge of squaring the circle with a compass and straightedge. The decimal digits of appear to be randomly distributed, but no proof of this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
