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Degree Of 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 Traffic lights, traffic signals, or stoplights – also known as robots in South Africa, Zambia, and Namibia – are signaling devices positioned at intersection (road), road intersections, pedestrian crossings, and other locations in order t ... 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 i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Traffic Engineering (transportation)
Traffic engineering is a branch of civil engineering that uses engineering techniques to achieve the safe and efficient movement of people and goods on roadways. It focuses mainly on research for safe and efficient traffic flow, such as road geometry, sidewalks and crosswalks, cycling infrastructure, traffic signs, road surface markings and traffic lights. Traffic engineering deals with the functional part of transportation system, except the infrastructures provided. Traffic engineering is closely associated with other disciplines: *Transport engineering *Pavement engineering *Bicycle transportation engineering *Highway engineering *Transportation planning *Urban planning *Human factors, Human factors engineering Typical traffic engineering projects involve designing traffic control device installations and modifications, including traffic signals, signs, and pavement markings. However, traffic engineers also consider traffic safety by investigating locations with high crash ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Passenger Car Unit
Passenger car equivalent (PCE) or passenger car unit (PCU) is a metric used in transportation engineering to assess traffic-flow rate on a highway. A passenger car equivalent is essentially the impact that a mode of transport has on traffic variables (such as headway, speed, density) compared to a single car. Traffic studies and/or analysis must be done to obtain the number of trips, which shall then be converted to PCUs based on the above standards. Each region has its own manual with regards to PCU equivalence factors. Highway capacity is measured in PCE/hour daily. A common method used in the US is the density method. However, the PCU values derived from the density method are based on underlying homogeneous traffic concepts such as strict lane discipline, car following, and a vehicle fleet that does not vary greatly in width. On the other hand, highways in India carry heterogeneous traffic, where road space is shared among many traffic modes with different physical dimens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Traffic Signal
Traffic lights, traffic signals, or stoplights – also known as robots in South Africa, Zambia, and Namibia – are signaling devices positioned at intersection (road), road intersections, pedestrian crossings, and other locations in order to control the flow of traffic. Traffic lights usually consist of three signals, transmitting meaningful information to road users through colours and symbols, including arrows and bicycles. The usual traffic light colours are red to stop traffic, Amber (color), amber for traffic change, and green to allow traffic to proceed. These are arranged vertically or horizontally in that order. Although this is internationally standardised, variations in traffic light sequences and laws exist on national and local scales. Traffic lights were first introduced in December 1868 on Parliament Square in London to reduce the need for police officers to control traffic. Since then, electricity and computerised control have advanced traffic light technolog ... [...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, resulting in many of the roads becoming obsolete. When traffic demand is great enough that the interaction between vehicles slows the traffic stream, this results in congestion. While congestion is a possibility for any mode of transportation, this article will focus on automobile congestion on public roads. Mathematically, traffic is modeled as a flow through a fixed point on the route, analogously to fluid dynamics. 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 or a tailback. Drivers can become frustrated and engage in road rage. Drivers and driver-focused r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
