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Three-phase Traffic Theory
Three-phase traffic theory is a theory of traffic flow developed by Boris Kerner between 1996 and 2002. It focuses mainly on the explanation of the physics of traffic breakdown and resulting congested traffic on highways. Kerner describes three phases of traffic, while the classical theories based on the fundamental diagram of traffic flow have two phases: ''free flow'' and ''congested traffic''. Kerner’s theory divides congested traffic into two distinct phases, ''synchronized flow'' and ''wide moving jam'', bringing the total number of phases to three: # Free flow (''F'') # Synchronized flow (''S'') # Wide moving jam (''J'') The word "wide" is used even though it is the length of the traffic jam that is being referred to. A phase is defined as a ''state in space and time.'' Free flow (''F'') In free traffic flow, empirical data show a positive correlation between the flow rate q (in vehicles per unit time) and vehicle density k (in vehicles per unit distance). This relation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Theory
A theory is a systematic and rational form of abstract thinking about a phenomenon, or the conclusions derived from such thinking. It involves contemplative and logical reasoning, often supported by processes such as observation, experimentation, and research. Theories can be scientific, falling within the realm of empirical and testable knowledge, or they may belong to non-scientific disciplines, such as philosophy, art, or sociology. In some cases, theories may exist independently of any formal discipline. In modern science, the term "theory" refers to Scientific theory, scientific theories, a well-confirmed type of explanation of nature, made in a way Consistency, consistent with the scientific method, and fulfilling the Scientific theory#Characteristics of theories, criteria required by modern science. Such theories are described in such a way that scientific tests should be able to provide Empirical evidence, empirical support for it, or Empirical evidence, empirical contradi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Autonomous Car
A self-driving car, also known as an autonomous car (AC), driverless car, robotic car or robo-car, is a car that is capable of operating with reduced or no User input, human input. They are sometimes called robotaxi, robotaxis, though this term refers specifically to self-driving cars operated for a ridesharing company. Self-driving cars are responsible for all driving activities, such as perceiving the environment, monitoring important systems, and controlling the vehicle, which includes navigating from origin to destination. , no system has achieved full autonomy (SAE Level 5). In December 2020, Waymo was the first to offer rides in self-driving taxis to the public in limited geographic areas (SAE Level 4), and offers services in Arizona (Phoenix) and California (San Francisco and Los Angeles). In June 2024, after a Waymo self-driving taxi crashed into a utility pole in Phoenix, Arizona, all 672 of its Jaguar I-Pace vehicles were recalled after they were found to have susc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Mathematical Modeling
A mathematical model is an abstract and concrete, abstract description of a concrete system using mathematics, mathematical concepts and language of mathematics, language. The process of developing a mathematical model is termed ''mathematical modeling''. Mathematical models are used in applied mathematics and in the natural sciences (such as physics, biology, earth science, chemistry) and engineering disciplines (such as computer science, electrical engineering), as well as in non-physical systems such as the social sciences (such as economics, psychology, sociology, political science). It can also be taught as a subject in its own right. The use of mathematical models to solve problems in business or military operations is a large part of the field of operations research. Mathematical models are also used in music, linguistics, and philosophy (for example, intensively in analytic philosophy). A model may help to explain a system and to study the effects of different components, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Kerner’s Breakdown Minimization Principle
Boris S. Kerner (born 1947) is a German physicist and civil engineer who created three phase traffic theory. The three phase traffic theory is the framework for the description of empirical vehicular traffic states in three traffic phases: (i) free traffic flow (F), (ii) synchronized traffic flow (S), and (iii) wide moving jam (J). The synchronized traffic flow and wide moving jam phases belong to congested traffic. Biography Kerner is an engineer and physicist. He was born in Moscow, Soviet Union in 1947 and graduated from the Moscow Technical University MIREA in 1972. Boris Kerner was received Ph.D. and Sc.D. (Doctor of Sciences) degrees in the Academy of Sciences of the Soviet Union, respectively, in 1979 and 1986. Between 1972 and 1992, his major interests include the physics of semiconductors, plasma and solid state physics. During this time, Boris Kerner together with V.V. Osipov developed a theory of Autosolitons – solitary intrinsic states, which form in a br ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Nucleation
In thermodynamics, nucleation is the first step in the formation of either a new Phase (matter), thermodynamic phase or Crystal structure, structure via self-assembly or self-organization within a substance or mixture. Nucleation is typically defined to be the process that determines how long an observer has to wait before the new phase or self-organized structure appears. For example, if a volume of water is cooled (at atmospheric pressure) significantly below 0°C, it will tend to Freezing, freeze into ice, but volumes of water cooled only a few degrees below 0°C often stay completely free of ice for long periods (supercooling). At these conditions, nucleation of ice is either slow or does not occur at all. However, at lower temperatures nucleation is fast, and ice crystals appear after little or no delay. Nucleation is a common mechanism which generates first-order phase transitions, and it is the start of the process of forming a new thermodynamic phase. In contrast, new phas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Overtaking
Overtaking or passing is the act of one vehicle going past another slower moving vehicle, travelling in the same direction, on a road. The lane used for overtaking another vehicle is often a passing lane farther from the road shoulder, which is to the left in places that drive on the right and to the right in places that drive on the left. Rules of overtaking In English-speaking countries On a single carriageway, single-carriageway/undivided-highway road, the lane used for overtaking is often the same lane that is used by oncoming traffic. An overtaking vehicle must be able to see clearly ahead of them for the entire overtaking manoeuvre plus a margin of error. For example, in New Zealand it's instructed in the Road Code that an overtaking driver must be able to see at least of clear road in front of them as they finish the passing manoeuvre. In the UK, guidance for passing and overtaking is given in rules 162-169 of the Highway Code. In some jurisdictions, the "overtaking ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |