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In three-phase traffic theory, traffic breakdown is explained by the F → S transition occurring in a metastable free flow. Probably the most important consequence of that is the existence of a range of highway capacities between some maximum and minimum capacities.
According to the definition [S] this pattern of congested traffic belongs to the "synchronized flow" traffic phase (Fig. 2 (a) and (b)). Fig.2. Empirical spatiotemporal common features of traffic congestion and the associated traffic phase definitions in Kerner's theory: (a) Measured data of average vehicle speed in time and space.
Three-phase traffic theory is an alternative theory of traffic flow created by Boris Kerner at the end of 1990's [24] [25] [26] (for reviews, see the books [27] [28] [29]). Probably the most important result of the three-phase theory is that at any time instance there is a range of highway capacities of free flow at a bottleneck.
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 [3] [4] or (informally) a traffic snarl-up [5] [6] or a tailback. [7] Drivers can become frustrated and engage in road rage. Drivers and ...
Braess's paradox is the observation that adding one or more roads to a road network can slow down overall traffic flow through it. The paradox was first discovered by Arthur Pigou in 1920, [1] and later named after the German mathematician Dietrich Braess in 1968.
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 rates and developing countermeasures to reduce crashes.
The first mathematical model of traffic flow in the framework of Kerner's three-phase traffic theory that mathematical simulations can show and explain traffic breakdown by an F → S phase transition in the metastable free flow at the bottleneck was the Kerner-Klenov stochastic microscopic traffic flow model introduced in 2002. [46]
In the study of traffic flow theory, the flow-density diagram is used to determine the traffic state of a roadway. Currently, there are two types of flow density graphs: parabolic and triangular. Academia views the triangular flow-density curve as more the accurate representation of real world events. The triangular curve consists of two vectors.