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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 con ... [...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 engineering Typical traffic engineering projects involve designing traffic control device installations and modifications, including traffic signals, signs, and pavement markings. Examples of Engineering Plans include pole engineering analysis and Storm Water Prevention Programs (SWPP). However ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |