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Newell's Car-following Model
In traffic flow theory, Newell’s car-following model is a method used to determine how vehicles follow one another on a roadway. The main idea of this model is that a vehicle will maintain a minimum space and time gap between it and the vehicle that precedes it. Thus, under congested conditions, if the leading car changes its speed, the following vehicle will also change speed at a point in time-space along the traffic wave speed, ''-w''.Newell G.F. (2002) A simplified car-following theory: a lower order model. Institute of Transportation Studies, University of California, Berkeley. Overview Assuming the fundamental diagram (flow-density) is a triangular function, a traffic state ''A'' with speed ''vA'' and density ''kA'' can be assumed in the congestion region. The density on the roadway can be determined using the spacing between vehicles and is computed simply the equation: ''kA = 1/sA'' Geometric relations from the fundamental diagram can be used to calculate the density ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Traffic Flow Theory
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] |
Traffic Congestion
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] |
Traffic Wave
Traffic waves, also called stop waves, ghost jams, traffic snakes or traffic shocks, are traveling disturbances in the distribution of cars on a highway. Traffic waves travel backwards relative to the cars themselves. Relative to a fixed spot on the road the wave can move with, or against the traffic, or even be stationary (when the wave moves away from the traffic with exactly the same speed as the traffic). Traffic waves are a type of traffic jam. A deeper understanding of traffic waves is a goal of the physical study of traffic flow, in which traffic itself can often be seen using techniques similar to those used in fluid dynamics. It is related to the accordion effect. Mitigation It has been saidTraffic Wave Experiments William J. Beaty, 1998 that by knowing how traffic waves are created, drivers can sometimes reduce their effects ... [...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 graphicall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Time Distance
Distance is a numerical or occasionally qualitative measurement of how far apart objects or points are. In physics or everyday usage, distance may refer to a physical length or an estimation based on other criteria (e.g. "two counties over"). Since spatial cognition is a rich source of conceptual metaphors in human thought, the term is also frequently used metaphorically to mean a measurement of the amount of difference between two similar objects (such as statistical distance between probability distributions or edit distance between strings of text) or a degree of separation (as exemplified by distance between people in a social network). Most such notions of distance, both physical and metaphorical, are formalized in mathematics using the notion of a metric space. In the social sciences, distance can refer to a qualitative measurement of separation, such as social distance or psychological distance. Distances in physics and geometry The distance between physical locatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Normal Driver
Normal(s) or The Normal(s) may refer to: Film and television * ''Normal'' (2003 film), starring Jessica Lange and Tom Wilkinson * ''Normal'' (2007 film), starring Carrie-Anne Moss, Kevin Zegers, Callum Keith Rennie, and Andrew Airlie * ''Normal'' (2009 film), an adaptation of Anthony Neilson's 1991 play ''Normal: The Düsseldorf Ripper'' * ''Normal!'', a 2011 Algerian film * ''The Normals'' (film), a 2012 American comedy film * "Normal" (''New Girl''), an episode of the TV series Mathematics * Normal (geometry), an object such as a line or vector that is perpendicular to a given object * Normal basis (of a Galois extension), used heavily in cryptography * Normal bundle * Normal cone, of a subscheme in algebraic geometry * Normal coordinates, in differential geometry, local coordinates obtained from the exponential map (Riemannian geometry) * Normal distribution, the Gaussian continuous probability distribution * Normal equations, describing the solution of the linear least sq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cautious Driver
Caution may refer to: * A precautionary statement, describing a potential hazard * A police caution, an alternative to prosecution for a criminal offence in some countries such as the United Kingdom and Australia * A statement read by a police officer to a suspect to inform them of their rights, in particular to silence. See e.g.: ** ''Miranda'' warning in the United States ** Right to silence in England and Wales **Right to silence, which discusses the international situation * Yellow card (sports) * La Caution, a French hip hop duo * Caution flag, in auto racing * ''Caution (Do Not Stop On Tracks)'', a song by the Grateful Dead * ''Caution'' (Hot Water Music album), 2002 * ''Caution'' (Left Spine Down album), 2011, or the title track * ''Caution'', a snippet song by XXXTentacion Jahseh Dwayne Ricardo Onfroy (January 23, 1998 – June 18, 2018), known professionally as XXXTentacion, was an American rapper and singer-songwriter. Though a controversial figure due to his ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aggressive Driver
Aggression is overt or covert, often harmful, social interaction with the intention of inflicting damage or other harm upon another individual; although it can be channeled into creative and practical outlets for some. It may occur either reactively or without provocation. In humans, aggression can be caused by various triggers, from frustration due to blocked goals to feeling disrespected. Human aggression can be classified into direct and indirect aggression; whilst the former is characterized by physical or verbal behavior intended to cause harm to someone, the latter is characterized by behavior intended to harm the social relations of an individual or group. In definitions commonly used in the social sciences and behavioral sciences, aggression is an action or response by an individual that delivers something unpleasant to another person. Some definitions include that the individual must intend to harm another person. In an interdisciplinary perspective, aggression is regar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annual Average Daily Traffic
Annual average daily traffic, abbreviated AADT, is a measure used primarily in transportation planning, transportation engineering and retail location selection. Traditionally, it is the total volume of vehicle traffic of a highway or road for a year divided by 365 days. AADT is a simple, but useful, measurement of how busy the road is. AADT is the standard measurement for vehicle traffic load on a section of road, and the basis for most decisions regarding transport planning, or to the environmental hazards of pollution related to road transport. Uses One of the most important uses of AADT is for determining funding for the maintenance and improvement of highways. In the United States the amount of federal funding a state will receive is related to the total traffic measured across its highway network. Each year on June 15, every state in the United States submits Highway Performance Monitoring System HPMS">Highway Performance Monitoring System">Highway Performance Monitoring Sy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gipps' Model
Gipps' model is a mathematical model for describing car-following behaviour by motorists in the United Kingdom. The model is named after Peter G. Gipps who developed it in the late-1970s under S.R.C. grants at the Transport Operations Research Group at the University of Newcastle-Upon-Tyne and the Transport Studies Group at the University College London. Gipps' model is based directly on driver behavior and expectancy for vehicles in a stream of traffic. Limitations on driver and vehicle parameters for safety purposes mimic the traits of vehicles following vehicles in the front of the traffic stream. Gipps' model is differentiated by other models in that Gipps uses a timestep within the function equal to \tau to reduce the computation required for numerical analysis. Introduction The method of modeling individual cars along a continuous space originates with Chandler et al. (1958), Gazis et al. (1961), Lee (1966) and Bender and Fenton (1972),Gipps, P. G. 1981 A behavioural car ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intelligent Driver Model
In traffic flow modeling, the intelligent driver model (IDM) is a time-continuous car-following model for the simulation of freeway and urban traffic. It was developed by Treiber, Hennecke and Helbing in 2000 to improve upon results provided with other "intelligent" driver models such as Gipps' model, which loses realistic properties in the deterministic limit. Model definition As a car-following model, the IDM describes the dynamics of the positions and velocities of single vehicles. For vehicle \alpha, x_\alpha denotes its position at time t, and v_\alpha its velocity. Furthermore, l_\alpha gives the length of the vehicle. To simplify notation, we define the ''net distance'' s_\alpha := x_ - x_\alpha - l_, where \alpha - 1 refers to the vehicle directly in front of vehicle \alpha, and the velocity difference, or ''approaching rate'', \Delta v_\alpha := v_\alpha - v_. For a simplified version of the model, the dynamics of vehicle \alpha are then described by the following two o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Traffic Simulation
Traffic simulation or the simulation of transportation systems is the computer simulation, mathematical modeling of transportation systems (e.g., freeway junctions, arterial routes, roundabouts, downtown grid systems, etc.) through the application of computer software to better help plan, design, and operate transportation systems. Simulation of transportation systems started over forty years ago, and is an important area of discipline in traffic engineering (transportation), traffic engineering and transportation planning today. Various national and local transportation agencies, academic institutions and consulting firms use simulation to aid in their management of transportation networks. Simulation in transportation is important because it can study models too complicated for analytical or numerical treatment, can be used for experimental studies, can study detailed relations that might be lost in analytical or numerical treatment and can produce attractive visual demonstrations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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